subject:(laser beam)

University of the Western Cape

1. Ratsibi, Humbelani Edzani. Laser drilling of metals and glass using zero-order bessel beams .

Degree: 2013, University of the Western Cape

► This dissertation consists of two main sections. The first section focuses on generating zero order Bessel beams using axicons. An axicon with an opening angle… (more)

▼ This dissertation consists of two main sections. The first section focuses on generating zero order Bessel beams using axicons. An axicon with an opening angle y = 5⁰ was illuminated with a Gaussian beam of width ω₀ = 1.67 mm from a cw fiber laser with central wavelength λ = 1064 nm to generate zero order Bessel beams with a central spot radius r₀ = 8.3 ± 0.3 μm and propagation distance ½zmax = 20.1 ± 0.5 mm. The central spot size of a Bessel beam changes slightly along the propagation distance. The central spot radius r₀ can be varied by changing the opening angle of the axicon, y, and the wavelength of the beam. The second section focuses on applications of the generated Bessel beams in laser microdrilling. A Ti:Sapphire pulsed femtosecond laser (λ = 775 nm, ω₀ = 2.5 mm, repetition rate kHz, pulse energy mJ, and pulse duration fs) was used to generate the Bessel beams for drilling stainless steel thin sheets of thickness 50 μm and 100 μm and microscopic glass slides 1 mm thick. The central spot radius was r₀ = 15.9 ± 0.3 μm and ½zmax = 65.0 ± 0.5 mm. The effect of the Bessel beam shape on the quality of the holes was analysed and the results were discussed. It was observed that Bessel beams drill holes of better quality on transparent microscopic glass slides than on stainless steel sheet. The holes drilled on stainless steel sheets deviated from being circular on both the top and bottom surface for both thicknesses. However the holes maintained the same shape on both sides of each sample, indicating that the walls are close to being parallel. The holes drilled on the glass slides were circular and their diameters could be measured. The measured diameter (15.4±0.3 μm) of the hole is smaller than the diameter of the central spot (28.2 ± 0.1 μm) of the Bessel beam. Increasing the pulse energy increased the diameter of the drilled hole to a value close to the measured diameter of the central spot. Advisors/Committee Members: Halindintwali, S (advisor), Burger, H. P (advisor), Forbes, A (advisor).

Subjects/Keywords: Gaussian beam; Bessel beams; Laser beams; Laser drilling; Laser beam shaping

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APA (6^th Edition):

Ratsibi, H. E. (2013). Laser drilling of metals and glass using zero-order bessel beams . (Thesis). University of the Western Cape. Retrieved from http://hdl.handle.net/11394/5428

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Ratsibi, Humbelani Edzani. “Laser drilling of metals and glass using zero-order bessel beams .” 2013. Thesis, University of the Western Cape. Accessed March 09, 2021. http://hdl.handle.net/11394/5428.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Ratsibi, Humbelani Edzani. “Laser drilling of metals and glass using zero-order bessel beams .” 2013. Web. 09 Mar 2021.

Vancouver:

Ratsibi HE. Laser drilling of metals and glass using zero-order bessel beams . [Internet] [Thesis]. University of the Western Cape; 2013. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11394/5428.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Ratsibi HE. Laser drilling of metals and glass using zero-order bessel beams . [Thesis]. University of the Western Cape; 2013. Available from: http://hdl.handle.net/11394/5428

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Minnesota

2. Tilseth, Erik. Spatial Mode Selection in a Passively Coupled Fiber Laser: Theory and Experiment.

Degree: M.S.E.E., Electrical/Computer Engineering, 2019, University of Minnesota

URL: http://hdl.handle.net/11299/208964

► In this thesis, self-phasing due to spatial mode selection in a two-element passively coupled fiber laser is studied. The fields emitted by a two-core ytterbium… (more)

Subjects/Keywords: fiber lasers; laser arrays; laser beam combining

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APA (6^th Edition):

Tilseth, E. (2019). Spatial Mode Selection in a Passively Coupled Fiber Laser: Theory and Experiment. (Masters Thesis). University of Minnesota. Retrieved from http://hdl.handle.net/11299/208964

Chicago Manual of Style (16^th Edition):

Tilseth, Erik. “Spatial Mode Selection in a Passively Coupled Fiber Laser: Theory and Experiment.” 2019. Masters Thesis, University of Minnesota. Accessed March 09, 2021. http://hdl.handle.net/11299/208964.

MLA Handbook (7^th Edition):

Tilseth, Erik. “Spatial Mode Selection in a Passively Coupled Fiber Laser: Theory and Experiment.” 2019. Web. 09 Mar 2021.

Vancouver:

Tilseth E. Spatial Mode Selection in a Passively Coupled Fiber Laser: Theory and Experiment. [Internet] [Masters thesis]. University of Minnesota; 2019. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11299/208964.

Council of Science Editors:

Tilseth E. Spatial Mode Selection in a Passively Coupled Fiber Laser: Theory and Experiment. [Masters Thesis]. University of Minnesota; 2019. Available from: http://hdl.handle.net/11299/208964

3. Slezák Ondřej. Self-navigation of laser beams on injected IFE targets using SBS PCM technology: conceptual design of the method .

Degree: 2012, Czech University of Technology

URL: http://hdl.handle.net/10467/13343

Self-navigation of laser beams on IFE targets using SBS PCM; Self-navigation of laser beams on IFE targets using SBS PCM Advisors/Committee Members: Kálal Milan (advisor).

Subjects/Keywords: Brillouin scattering; laser fusion; laser beam combination

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APA (6^th Edition):

Ondřej, S. (2012). Self-navigation of laser beams on injected IFE targets using SBS PCM technology: conceptual design of the method . (Thesis). Czech University of Technology. Retrieved from http://hdl.handle.net/10467/13343

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Ondřej, Slezák. “Self-navigation of laser beams on injected IFE targets using SBS PCM technology: conceptual design of the method .” 2012. Thesis, Czech University of Technology. Accessed March 09, 2021. http://hdl.handle.net/10467/13343.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Ondřej, Slezák. “Self-navigation of laser beams on injected IFE targets using SBS PCM technology: conceptual design of the method .” 2012. Web. 09 Mar 2021.

Vancouver:

Ondřej S. Self-navigation of laser beams on injected IFE targets using SBS PCM technology: conceptual design of the method . [Internet] [Thesis]. Czech University of Technology; 2012. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/10467/13343.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Ondřej S. Self-navigation of laser beams on injected IFE targets using SBS PCM technology: conceptual design of the method . [Thesis]. Czech University of Technology; 2012. Available from: http://hdl.handle.net/10467/13343

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

4. Kabeya, David. Montée en brillance des réseaux de lasers à fibre : Nouvelle approche par diagnostic à contraste de phase dans une boucle d’optimisation : Brightness enhancement in tilled-aperture laser systems : Innovative method associating a phase-contrast like filter with an optimization loop.

Degree: Docteur es, Electronique des Hautes Fréquences, Photonique et Systèmes, 2016, Limoges

URL: http://www.theses.fr/2016LIMO0116

►

Les méthodes de combinaison cohérente sont rapidement apparues comme très prometteuses dans la course à la puissance des sources lasers. Cela s’explique par le fait… (more)

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Les méthodes de combinaison cohérente sont rapidement apparues comme très prometteuses dans la course à la puissance des sources lasers. Cela s’explique par le fait que la puissance autour de l’axe de propagation évolue selon une loi quadratique avec le nombre de faisceaux combinés. Mes premiers travaux ont porté sur la montée en puissance de pompage dans les systèmes de mise en phase passive par auto-organisation. Pour la première fois, nous avons mis en évidence à la fois expérimentalement et numériquement, qu’au-delà du seuil laser, le filtrage spectral intracavité dû à la structure interférométrique du système laser, est un des principaux facteurs limitant l’obtention de qualités de phasage élevées. L’augmentation du nombre d’émetteurs accentue la dégradation de l’efficacité de combinaison avec la montée en puissance, montrant l’incapacité de ce type de méthode à combiner efficacement un grand nombre d’émetteurs lasers de forte puissance. Par la suite, mes travaux ont porté sur l’étude d’une méthode innovante de phasage actif, mise au point à XLIM. Le principe de cette méthode associe un filtrage optique de type contraste de phase, à un algorithme d’optimisation réduisant les écarts de phases entre émetteurs. Les calculs et expériences ont mis en évidence la très faible sensibilité de la méthode au nombre d’émetteurs mis en jeu. Les démonstrations de combinaison cohérente de 7 à 37 émetteurs fibrés délivrant jusqu’à 5W chacun ont été faites. Ce dernier résultat constitue aujourd’hui un record en termes de nombre d’émetteurs combinés de manière active. L’efficacité de combinaison en champ lointain a été estimée à une valeur élevée de 94%, correspondant à une erreur de phase résiduelle d’environ λ/25. Le faible nombre d’itérations d’algorithme nécessaires pour converger a permis de corriger les fluctuations de phase sur une bande d’environ 1kHz.

Coherent laser beam combining techniques rapidly appeared highly promising in the field of ultra-high power laser sources. Indeed, the combined intensity around the propagation axis follows a quadratic law with the number of combined emitters. The first part of my work has been focused on passive phasing techniques, based on self-organization properties of coupled lasers. We have shown, both numerically and experimentally, that the intracavity filtering function due to the interferometric nature of the set-up, is an intrinsic reason for combining efficiency decrease far above laser threshold. The decrease goes steeper when the number of combined laser increases, making that kind of system inappropriate for coherently combining a large number of lasers delivering high power. The second part of my work consisted in studying an innovative active phasing method that associates a phase-contrast like filter with an optimization algorithm reducing phase errors between emitters. Both simulations and experiments showed the weak sensitivity of this method to the number of combined emitters. We demonstrated the phasing of 7 to 37 fiber lasers, delivering up to 5W each. To the best…

Advisors/Committee Members: Desfarges-Berthelemot, Agnès (thesis director), Kermène, Vincent (thesis director).

Subjects/Keywords: Combinaison cohérente de laser; Laser à fibre; Coherent laser beam combining; Fiber laser; 621.366

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APA (6^th Edition):

Kabeya, D. (2016). Montée en brillance des réseaux de lasers à fibre : Nouvelle approche par diagnostic à contraste de phase dans une boucle d’optimisation : Brightness enhancement in tilled-aperture laser systems : Innovative method associating a phase-contrast like filter with an optimization loop. (Doctoral Dissertation). Limoges. Retrieved from http://www.theses.fr/2016LIMO0116

Chicago Manual of Style (16^th Edition):

Kabeya, David. “Montée en brillance des réseaux de lasers à fibre : Nouvelle approche par diagnostic à contraste de phase dans une boucle d’optimisation : Brightness enhancement in tilled-aperture laser systems : Innovative method associating a phase-contrast like filter with an optimization loop.” 2016. Doctoral Dissertation, Limoges. Accessed March 09, 2021. http://www.theses.fr/2016LIMO0116.

MLA Handbook (7^th Edition):

Kabeya, David. “Montée en brillance des réseaux de lasers à fibre : Nouvelle approche par diagnostic à contraste de phase dans une boucle d’optimisation : Brightness enhancement in tilled-aperture laser systems : Innovative method associating a phase-contrast like filter with an optimization loop.” 2016. Web. 09 Mar 2021.

Vancouver:

Kabeya D. Montée en brillance des réseaux de lasers à fibre : Nouvelle approche par diagnostic à contraste de phase dans une boucle d’optimisation : Brightness enhancement in tilled-aperture laser systems : Innovative method associating a phase-contrast like filter with an optimization loop. [Internet] [Doctoral dissertation]. Limoges; 2016. [cited 2021 Mar 09]. Available from: http://www.theses.fr/2016LIMO0116.

Council of Science Editors:

Kabeya D. Montée en brillance des réseaux de lasers à fibre : Nouvelle approche par diagnostic à contraste de phase dans une boucle d’optimisation : Brightness enhancement in tilled-aperture laser systems : Innovative method associating a phase-contrast like filter with an optimization loop. [Doctoral Dissertation]. Limoges; 2016. Available from: http://www.theses.fr/2016LIMO0116

UCLA

5. Xi, Yunfeng. Ionization injection plasma wakefield acceleration.

Degree: Physics, 2016, UCLA

URL: http://www.escholarship.org/uc/item/5gh0k91r

► Plasma-based acceleration, either driven by laser (LWFA) or driven by electron beam (PWFA) has the potential of accelerating electrons to GeV in a few cen-… (more)

Subjects/Keywords: Physics; acceleration; beam; laser; plasma; wakefield

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APA (6^th Edition):

Xi, Y. (2016). Ionization injection plasma wakefield acceleration. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/5gh0k91r

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Xi, Yunfeng. “Ionization injection plasma wakefield acceleration.” 2016. Thesis, UCLA. Accessed March 09, 2021. http://www.escholarship.org/uc/item/5gh0k91r.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Xi, Yunfeng. “Ionization injection plasma wakefield acceleration.” 2016. Web. 09 Mar 2021.

Vancouver:

Xi Y. Ionization injection plasma wakefield acceleration. [Internet] [Thesis]. UCLA; 2016. [cited 2021 Mar 09]. Available from: http://www.escholarship.org/uc/item/5gh0k91r.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Xi Y. Ionization injection plasma wakefield acceleration. [Thesis]. UCLA; 2016. Available from: http://www.escholarship.org/uc/item/5gh0k91r

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Tulane University

6. Ibrahim M. Alhroob. Querying early product chemistry in a complex process: A cold molecular beam approach for triglyceride pyrolysis: Cold molecular beam study of Triglycerides pyrolysis chemistry.

Degree: 2020, Tulane University

URL: https://digitallibrary.tulane.edu/islandora/object/tulane:120568

►

[email protected]

A cold molecular beam approach has been pioneered to investigate the pyrolysis reactions of triglycerides (TGs) as a function of temperature. Traditionally, an established… (more)

▼

[email protected]

A cold molecular beam approach has been pioneered to investigate the pyrolysis reactions of triglycerides (TGs) as a function of temperature. Traditionally, an established repertoire of laser techniques is utilized for multiple species present, which has been extensively used for a detailed study of specifically targeted species that are often novel and reactive. Instead, we have applied these methods for the mass characterization of numerous product species as they appeared. Unlike traditional batch reactor studies of pyrolysis, where terminal products are identified and characterized generally using GC/MS methods, herein, product analysis was conducted in real time. Experiments were performed by recording mass spectra as a function of increasing sample temperature. For clearer results and interpretation, most studies employed model TGs containing a single fatty acid, such as oleic or stearic acid. Soft photoionization was conducted using 118 and 266 nm laser-based pulses. Time-of-flight mass spectroscopy (TOF-MS) was conducted after each photoionization pulse. Several novel direct observations include 1) the observation of initial cracking temperatures and the formation of non-aromatic and aromatic products; 2) the determination of key factors for pyrolysis—fatty acid detachment from the glycerol backbone and subsequent fatty acid pyrolysis; 3) the growth of C6 and C7 fragments as an important precursor for following association reactions. The use of 266 nm pulses exclusively facilitated the sensitive and selective photoionization of aromatic products and, thus, the thorough examination of the evolving aromatic products. Unlike the batch reactor studies of terminal products, the molecular beam studies of aromatic products revealed the evolution to a small number of selective and relatively massive polycyclic aromatic hydrocarbons (PAH). It is deduced that in a batch reactor, these undetected products ultimately lead to solids and tars that are difficult to analyze. Our investigation revealed that hydrogen addition showed some effectiveness in inhibiting formation of large

1

Ibrahi M. Alhroob

Advisors/Committee Members: Rubtsov, Igor (Thesis advisor), School of Science & Engineering Chemistry (Degree granting institution).

Subjects/Keywords: Photoionization; Laser spectrometry; Molecular beam; Pyrolysis

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APA (6^th Edition):

Alhroob, I. M. (2020). Querying early product chemistry in a complex process: A cold molecular beam approach for triglyceride pyrolysis: Cold molecular beam study of Triglycerides pyrolysis chemistry. (Thesis). Tulane University. Retrieved from https://digitallibrary.tulane.edu/islandora/object/tulane:120568

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Alhroob, Ibrahim M.. “Querying early product chemistry in a complex process: A cold molecular beam approach for triglyceride pyrolysis: Cold molecular beam study of Triglycerides pyrolysis chemistry.” 2020. Thesis, Tulane University. Accessed March 09, 2021. https://digitallibrary.tulane.edu/islandora/object/tulane:120568.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Alhroob, Ibrahim M.. “Querying early product chemistry in a complex process: A cold molecular beam approach for triglyceride pyrolysis: Cold molecular beam study of Triglycerides pyrolysis chemistry.” 2020. Web. 09 Mar 2021.

Vancouver:

Alhroob IM. Querying early product chemistry in a complex process: A cold molecular beam approach for triglyceride pyrolysis: Cold molecular beam study of Triglycerides pyrolysis chemistry. [Internet] [Thesis]. Tulane University; 2020. [cited 2021 Mar 09]. Available from: https://digitallibrary.tulane.edu/islandora/object/tulane:120568.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Alhroob IM. Querying early product chemistry in a complex process: A cold molecular beam approach for triglyceride pyrolysis: Cold molecular beam study of Triglycerides pyrolysis chemistry. [Thesis]. Tulane University; 2020. Available from: https://digitallibrary.tulane.edu/islandora/object/tulane:120568

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Texas – Austin

7. -5609-6919. A bright source of cold atoms.

Degree: PhD, Physics, 2019, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/2954

► This dissertation describes a general approach of generating a high flux of cold atoms that can be confined in a magneto-optical trap. As an alternative… (more)

▼ This dissertation describes a general approach of generating a high flux of cold atoms that can be confined in a magneto-optical trap. As an alternative to the state-of-the-art laser cooling method, this approach widens our ability to cool and control atoms without relying on a specific atomic transition and availability of laser. In this dissertation I will discuss the design, construction of the experiment and characterization of a pulsed cold atom source in detail. This work is based on a new paradigm: entrainment of atoms in the carrier gas of a supersonic beam, followed by the magnetic deceleration and trapping. Our methodology is based on the supersonic beam created by the expansion of a dense carrier gas from a pulsed release of gas through a small aperture. Cold noble gas emerging from this pulsed high pressure supersonic nozzle acts as a carrier, into which atoms of interest are then entrained. In our studies with the lithium atoms, up to 10¹¹ atoms per pulse could be entrained into a supersonic beam of helium at a translation temperature of below 100 mK. The supersonic valve is typically operated at a rate of below 1 Hz in the experiment. A much larger flux can be achieved at a higher repetition rate. These atoms are moving at a speed of 500 ms⁻¹ and need to be decelerated almost to a complete stop, in order to be trapped and cooled to quantum degeneracy. A 2.5-meter long moving-trap magnetic decelerator with 480 coil pairs was built and characterized. Atoms moving at a speed around 500 ms⁻¹ were trapped and decelerated to various final velocities ranging from 400 ms⁻¹ to 50 ms⁻¹, at a resulting temperature of 30 mK and a flux of 10⁸ ~ 10⁹ atoms per pulse. This whole process takes place within only 10 ms, at a repetition rate of 100 Hz 10¹⁰ ~ 10¹¹ atoms can be delivered per second. This approach is very general compared to the laser cooling, since most atoms in the periodic table have a magnetic moment in their ground state or can be optically pumped to a long-lived para-magnetic metastable state. In this dissertation, I show the working principle of each component of our experiment and characterize the atom beam at multiple stages. I describe in detail the construction and optimization of our magnetic decelerator, and demonstrate the control and monitoring system with the experiment results. Also implemented in this work is a flexible laser system that is composed of a reference diode laser and two tapered amplifiers to control and probe the internal states of atoms, as well as provide the trapping force. I also explore the optical molasses and chirped cooling techniques which help load the atoms into a magneto-optical trap. The successful demonstration of this method of creating a cold atom source leads us to believe that the magnetically decelerated supersonic atoms will play an important role in the area of cold atom physics Advisors/Committee Members: Raizen, Mark G. (advisor), Niu, Qian (committee member), Hegelich, Bjorn (committee member), Caceres, Elena (committee member), Bajaj, Chandrajit (committee member).

Subjects/Keywords: Atomic physics; Cold atoms; Supersonic beam; Laser

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APA (6^th Edition):

-5609-6919. (2019). A bright source of cold atoms. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/2954

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-5609-6919. “A bright source of cold atoms.” 2019. Doctoral Dissertation, University of Texas – Austin. Accessed March 09, 2021. http://dx.doi.org/10.26153/tsw/2954.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-5609-6919. “A bright source of cold atoms.” 2019. Web. 09 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-5609-6919. A bright source of cold atoms. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2019. [cited 2021 Mar 09]. Available from: http://dx.doi.org/10.26153/tsw/2954.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-5609-6919. A bright source of cold atoms. [Doctoral Dissertation]. University of Texas – Austin; 2019. Available from: http://dx.doi.org/10.26153/tsw/2954

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Arizona

8. Whitsitt, Rebecca. Focal Volume Characterization of a Laser Scanning System .

Degree: 2020, University of Arizona

URL: http://hdl.handle.net/10150/648679

► Knife edge testing of a focused laser beam is a well-known method of observation of the position of focus. When this test is paired with… (more)

Subjects/Keywords: beam waist; knife edge; laser scanner; pinhole

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APA (6^th Edition):

Whitsitt, R. (2020). Focal Volume Characterization of a Laser Scanning System . (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/648679

Chicago Manual of Style (16^th Edition):

Whitsitt, Rebecca. “Focal Volume Characterization of a Laser Scanning System .” 2020. Masters Thesis, University of Arizona. Accessed March 09, 2021. http://hdl.handle.net/10150/648679.

MLA Handbook (7^th Edition):

Whitsitt, Rebecca. “Focal Volume Characterization of a Laser Scanning System .” 2020. Web. 09 Mar 2021.

Vancouver:

Whitsitt R. Focal Volume Characterization of a Laser Scanning System . [Internet] [Masters thesis]. University of Arizona; 2020. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/10150/648679.

Council of Science Editors:

Whitsitt R. Focal Volume Characterization of a Laser Scanning System . [Masters Thesis]. University of Arizona; 2020. Available from: http://hdl.handle.net/10150/648679

University of Minnesota

9. Kunkel, William. Passive coherent beam combining by gain effects in fiber lasers and spatial beam control in gradient refractive index media.

Degree: PhD, Electrical Engineering, 2018, University of Minnesota

URL: http://hdl.handle.net/11299/201689

► This thesis addresses two topics in coherent beam combining. First, a fiber laser with two parallel gain elements is considered, where the phase difference between… (more)

Subjects/Keywords: beam shaping; fiber lasers; GRIN; laser arrays; laser beam combining; phase retrieval

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APA (6^th Edition):

Kunkel, W. (2018). Passive coherent beam combining by gain effects in fiber lasers and spatial beam control in gradient refractive index media. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/201689

Chicago Manual of Style (16^th Edition):

Kunkel, William. “Passive coherent beam combining by gain effects in fiber lasers and spatial beam control in gradient refractive index media.” 2018. Doctoral Dissertation, University of Minnesota. Accessed March 09, 2021. http://hdl.handle.net/11299/201689.

MLA Handbook (7^th Edition):

Kunkel, William. “Passive coherent beam combining by gain effects in fiber lasers and spatial beam control in gradient refractive index media.” 2018. Web. 09 Mar 2021.

Vancouver:

Kunkel W. Passive coherent beam combining by gain effects in fiber lasers and spatial beam control in gradient refractive index media. [Internet] [Doctoral dissertation]. University of Minnesota; 2018. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11299/201689.

Council of Science Editors:

Kunkel W. Passive coherent beam combining by gain effects in fiber lasers and spatial beam control in gradient refractive index media. [Doctoral Dissertation]. University of Minnesota; 2018. Available from: http://hdl.handle.net/11299/201689

Brno University of Technology

10. Trost, Daniel. Porovnání technologie svařování materiálů laserem a svařování svazkem elektronů: Comparison of laser welding and electron beam welding technology.

Degree: 2019, Brno University of Technology

URL: http://hdl.handle.net/11012/66316

► Thesis presents a comparison of technical evaluation of two welding technologies – dismountable connection of two materials, in this case superalloy Inconel 718. On the… (more)

Subjects/Keywords: Inconel 718; svařování; laser; svazek elektronů; Inconel 718; welding; laser beam; electron beam

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APA (6^th Edition):

Trost, D. (2019). Porovnání technologie svařování materiálů laserem a svařování svazkem elektronů: Comparison of laser welding and electron beam welding technology. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/66316

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Trost, Daniel. “Porovnání technologie svařování materiálů laserem a svařování svazkem elektronů: Comparison of laser welding and electron beam welding technology.” 2019. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/66316.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Trost, Daniel. “Porovnání technologie svařování materiálů laserem a svařování svazkem elektronů: Comparison of laser welding and electron beam welding technology.” 2019. Web. 09 Mar 2021.

Vancouver:

Trost D. Porovnání technologie svařování materiálů laserem a svařování svazkem elektronů: Comparison of laser welding and electron beam welding technology. [Internet] [Thesis]. Brno University of Technology; 2019. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/66316.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Trost D. Porovnání technologie svařování materiálů laserem a svařování svazkem elektronů: Comparison of laser welding and electron beam welding technology. [Thesis]. Brno University of Technology; 2019. Available from: http://hdl.handle.net/11012/66316

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Arkansas

11. Ambuj, Anindya. Diffraction of Laguerre Gaussian Vortex Beams.

Degree: PhD, 2018, University of Arkansas

URL: https://scholarworks.uark.edu/etd/2761

► The natural phenomenon of waves bending around obstacles is diffraction. Spatial characteristics of the diffraction pattern depends on the incident wave field, the shape,… (more)

▼ The natural phenomenon of waves bending around obstacles is diffraction. Spatial characteristics of the diffraction pattern depends on the incident wave field, the shape, and size of the aperture. The diffraction of a plane wave of light by a slit and a circular aperture produce the sinc-squared and the Airy intensity patterns, respectively. On the contrary, the diffraction of Laguerre-Gauss vortex (LGV) beams by simple apertures such as a slit, circular apertures, and polygons show many unexpected features. LGV beams have ρ ` e i`φ transverse spatial dependence, where ρ is the distance from the beam axis, φ the azimuthal angle, and ` is the index of orbital angular momentum that corresponds to `~ of orbital angular momentum per photon. The LGV beams were produced from Hermite-Gauss beams using an astigmatic mode converter. The LGV beams were diffracted by a slit, circular apertures, and polygons. The far-field diffraction pattern was recorded. LGV beam of order ` when diffracted by a slit at the beam waist showed, ` + 1 fringes. The diffraction performed along the direction of propagation, away from the waist, showed a shear in the pattern, with maximum shear at Rayleigh range. As the slit was moved even further away, the diffraction pattern evolved into two dominant peaks irrespective of `. When LGV beams of order ` are diffracted by a circular aperture, the minima of the diffracted field depend on the zeros of ` + 1 order Bessel functions. The center of the diffraction pattern has a minimum for ` ≥ 1. When the beam axis and the aperture axis are laterally separated, this central minimum splits into ` minima. The diffraction of LGV beams by regular polygons created an optical lattice. The diffraction pattern by a regular polygon of n sides has n−fold symmetry for both even and odd n, unlike the 2n−fold symmetry for odd n, and n−fold for even n due to a plane wave. The center of the diffraction pattern is bright for ` = n, and multiples of n. The diffraction pattern has a repeating, nesting structure for ` > n. The experimental results are in good agreement with the theoretical predictions. Advisors/Committee Members: Surendra Singh, Reeta Vyas, Min Xiao.

Subjects/Keywords: Beam; Diffraction; Gaussian; Laguerre; Laser; Vortex; Plasma and Beam Physics

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APA (6^th Edition):

Ambuj, A. (2018). Diffraction of Laguerre Gaussian Vortex Beams. (Doctoral Dissertation). University of Arkansas. Retrieved from https://scholarworks.uark.edu/etd/2761

Chicago Manual of Style (16^th Edition):

Ambuj, Anindya. “Diffraction of Laguerre Gaussian Vortex Beams.” 2018. Doctoral Dissertation, University of Arkansas. Accessed March 09, 2021. https://scholarworks.uark.edu/etd/2761.

MLA Handbook (7^th Edition):

Ambuj, Anindya. “Diffraction of Laguerre Gaussian Vortex Beams.” 2018. Web. 09 Mar 2021.

Vancouver:

Ambuj A. Diffraction of Laguerre Gaussian Vortex Beams. [Internet] [Doctoral dissertation]. University of Arkansas; 2018. [cited 2021 Mar 09]. Available from: https://scholarworks.uark.edu/etd/2761.

Council of Science Editors:

Ambuj A. Diffraction of Laguerre Gaussian Vortex Beams. [Doctoral Dissertation]. University of Arkansas; 2018. Available from: https://scholarworks.uark.edu/etd/2761

University of Maryland

12. Nelson, William. Laser beam control, combining, and propagation in atmospheric turbulence.

Degree: Electrical Engineering, 2016, University of Maryland

URL: http://hdl.handle.net/1903/18273

► This dissertation is concerned with the control, combining, and propagation of laser beams through a turbulent atmosphere. In the first part we consider adaptive optics:… (more)

▼ This dissertation is concerned with the control, combining, and propagation of laser beams through a turbulent atmosphere. In the first part we consider adaptive optics: the process of controlling the beam based on information of the current state of the turbulence. If the target is cooperative and provides a coherent return beam, the phase measured near the beam transmitter and adaptive optics can, in principle, correct these fluctuations. However, for many applications, the target is uncooperative. In this case, we show that an incoherent return from the target can be used instead. Using the principle of reciprocity, we derive a novel relation between the field at the target and the scattered field at a detector. We then demonstrate through simulation that an adaptive optics system can utilize this relation to focus a beam through atmospheric turbulence onto a rough surface. In the second part we consider beam combining. To achieve the power levels needed for directed energy applications it is necessary to combine a large number of lasers into a single beam. The large linewidths inherent in high-power fiber and slab lasers cause random phase and intensity fluctuations occurring on sub-nanosecond time scales. We demonstrate that this presents a challenging problem when attempting to phase-lock high-power lasers. Furthermore, we show that even if instruments are developed that can precisely control the phase of high-power lasers; coherent combining is problematic for DE applications. The dephasing effects of atmospheric turbulence typically encountered in DE applications will degrade the coherent properties of the beam before it reaches the target. Finally, we investigate the propagation of Bessel and Airy beams through atmospheric turbulence. It has been proposed that these quasi-non-diffracting beams could be resistant to the effects of atmospheric turbulence. However, we find that atmospheric turbulence disrupts the quasi-non-diffracting nature of Bessel and Airy beams when the transverse coherence length nears the initial aperture diameter or diagonal respectively. The turbulence induced transverse phase distortion limits the effectiveness of Bessel and Airy beams for applications requiring propagation over long distances in the turbulent atmosphere. Advisors/Committee Members: Davis, Christopher C (advisor).

Subjects/Keywords: Optics; adaptive optics; atmospheric turbulence; beam combining; laser beam propagation

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APA (6^th Edition):

Nelson, W. (2016). Laser beam control, combining, and propagation in atmospheric turbulence. (Thesis). University of Maryland. Retrieved from http://hdl.handle.net/1903/18273

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Nelson, William. “Laser beam control, combining, and propagation in atmospheric turbulence.” 2016. Thesis, University of Maryland. Accessed March 09, 2021. http://hdl.handle.net/1903/18273.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Nelson, William. “Laser beam control, combining, and propagation in atmospheric turbulence.” 2016. Web. 09 Mar 2021.

Vancouver:

Nelson W. Laser beam control, combining, and propagation in atmospheric turbulence. [Internet] [Thesis]. University of Maryland; 2016. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/1903/18273.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Nelson W. Laser beam control, combining, and propagation in atmospheric turbulence. [Thesis]. University of Maryland; 2016. Available from: http://hdl.handle.net/1903/18273

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

13. Norkey, Gavendra. Optimization and experimental modeling of quality characteristics for difficult to laser cut aluminum alloy sheets.

Degree: Mechanical Engineering, 2014, Jaypee University of Engineering and Technology, Guna

URL: http://shodhganga.inflibnet.ac.in/handle/10603/18194

► Development of advanced engineering materials, stringent design requirement, intricate shape and unusual size and shape of the workpiece restrict the use of conventional machining process.… (more)

▼ Development of advanced engineering materials, stringent design requirement, intricate shape and unusual size and shape of the workpiece restrict the use of conventional machining process. Conventional sheet cutting methods have limitations regarding hardness of sheet material, demand of narrow kerf, complex shapes and intricate profiles. Hence, it was realized that new sheet cutting methods be developed with advanced characteristics known as non-conventional or Advanced Sheet Cutting Methods (ASCMs). Nowadays, many advance sheet cutting methods are being used in industry like Abrasive Jet Cutting (AJC), Water Jet Cutting (WJC), Abrasive Water Jet Cutting (AWJC) and Laser Beam Cutting (LBC) are the examples of ASCMs. AWJC and LBC are more popular due to their cutting capabilities. newlineLaser beam cutting is one of the widely applied ASCMs for cutting of complex shapes and intricate profiles in sheets of different advanced engineering materials. Excellent cut quality and narrow cut kerf are the key features of LBC. This feature maximizes the sheet metal usage by reducing the scrap. LBC is superior to any cutting method, conventional or non-conventional, because of material versatility, no wear or change of tool, high material utilization, production flexibility, high accuracy and edge quality. These unique characteristics of LBC are quite suitable for the improvement productivity. newlineLBC is a thermal energy based non-contact type advanced cutting process in which the material is removed by focusing the high energy density beam on the workpiece surface. Depending upon the prevailing condition, the material may be removed by different mechanism such as vaporization, fusion, reactive fusion, ablation and controlled fracture. The melted material is removed by the flow of high pressure coaxial assist gas jet. The assist gas jet accelerates the transformed material and ejects it from machining zone. The capability of the laser cutting mainly depends on the optical and thermal properties rather than mechanical properties. Advisors/Committee Members: Agrawal, Sanat, Dubey, Avanish Kumar.

Subjects/Keywords: Laser Beam; Laser cutting parameters of aluminum alloy sheetheet

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APA (6^th Edition):

Norkey, G. (2014). Optimization and experimental modeling of quality characteristics for difficult to laser cut aluminum alloy sheets. (Thesis). Jaypee University of Engineering and Technology, Guna. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/18194

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Norkey, Gavendra. “Optimization and experimental modeling of quality characteristics for difficult to laser cut aluminum alloy sheets.” 2014. Thesis, Jaypee University of Engineering and Technology, Guna. Accessed March 09, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/18194.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Norkey, Gavendra. “Optimization and experimental modeling of quality characteristics for difficult to laser cut aluminum alloy sheets.” 2014. Web. 09 Mar 2021.

Vancouver:

Norkey G. Optimization and experimental modeling of quality characteristics for difficult to laser cut aluminum alloy sheets. [Internet] [Thesis]. Jaypee University of Engineering and Technology, Guna; 2014. [cited 2021 Mar 09]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/18194.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Norkey G. Optimization and experimental modeling of quality characteristics for difficult to laser cut aluminum alloy sheets. [Thesis]. Jaypee University of Engineering and Technology, Guna; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/18194

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

14. Blecher, Jared Jacob. Numerical Modeling of Laser-silicon Interactions during Formation of Selective Emitters.

Degree: 2012, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/14560

► The formation of highly doped selective emitters improves the efficiency of silicon-based solar cells by lowering the contact resistance at the interface between the silicon… (more)

▼ The formation of highly doped selective emitters improves the efficiency of silicon-based solar cells by lowering the contact resistance at the interface between the silicon front surface and the metal contacts. The use of laser doping in which a laser locally melts the silicon substrate and rapidly incorporates the dopant into the silicon can provide faster processing speeds, lower energy inputs, and higher diffusion rates than other methods of forming selective emitters. A mathematical model, which solves for the temperature, velocity, and dopant concentration fields, is used to investigate the characteristics of the molten region during laser doping with a continuous-wave green laser (λ = 532 nm) moving over the sample at speeds up to 8 m/s and laser output powers ranging from 5 to 20 W. The calculated liquid pool widths and dopant distribution profiles are validated with published experimental results. The effects of fluid flow and diffusive movement on the final shape of the dopant distribution profiles are discussed, and figures are provided to illustrate each effect. Process maps are produced to illustrate how the size of the molten pool dimensions, the average dopant concentration, the relative shape of the dopant distribution, and silicon sheet resistance are impacted by the combination of power and scan speed. The molten pool depth and width are important in determining the diffusion profile and the front-side contact width during plating. High power solid state fiber and disk lasers combine faster processing speeds, deeper weld penetrations, and lower levels of work piece distortion. Both transmissive optics and reflective optics systems are commonly used. When using transmissive optics at high laser powers and prolonged periods of operation, changes in the focal length and beam diameter have been observed, and these changes adversely affect consistency of the processed materials. In this study, the properties of beams delivered using both transmissive and reflective optics systems from the exit of the process fiber through the final focusing optics have been characterized using commercial diagnostic tools. In the transmissive optics system, changes of nearly 8 mm in focal length have been measured with a 500 mm focal optic at 12 kW output power over several minutes of continuous operation. At powers above 4 kW, damage to the anti-reflective coating on a transmissive collimator resulted in a doubling in the beam diameter at the original focal position when using a 200 mm focal optic and a quadrupling of the beam diameter with a 500 mm focal optic. On the other hand, the performance of the reflective optics was not impacted by either increases in power or time at powers up to 12 kW during prolonged laser operation. Advisors/Committee Members: Todd Palmer, Thesis Advisor/Co-Advisor, Dr Tarasankar Deb Roy, Thesis Advisor/Co-Advisor, Suzanne E Mohney, Thesis Advisor/Co-Advisor.

Subjects/Keywords: laser doping; solar cell; photovoltaics; laser diagnostic; beam characterization

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APA (6^th Edition):

Blecher, J. J. (2012). Numerical Modeling of Laser-silicon Interactions during Formation of Selective Emitters. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/14560

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Blecher, Jared Jacob. “Numerical Modeling of Laser-silicon Interactions during Formation of Selective Emitters.” 2012. Thesis, Penn State University. Accessed March 09, 2021. https://submit-etda.libraries.psu.edu/catalog/14560.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Blecher, Jared Jacob. “Numerical Modeling of Laser-silicon Interactions during Formation of Selective Emitters.” 2012. Web. 09 Mar 2021.

Vancouver:

Blecher JJ. Numerical Modeling of Laser-silicon Interactions during Formation of Selective Emitters. [Internet] [Thesis]. Penn State University; 2012. [cited 2021 Mar 09]. Available from: https://submit-etda.libraries.psu.edu/catalog/14560.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Blecher JJ. Numerical Modeling of Laser-silicon Interactions during Formation of Selective Emitters. [Thesis]. Penn State University; 2012. Available from: https://submit-etda.libraries.psu.edu/catalog/14560

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Brno University of Technology

15. Rudyk, Martin. Analýza aplikací svazku elektronů v průmyslu: Analysis of application electron beam in industry.

Degree: 2019, Brno University of Technology

URL: http://hdl.handle.net/11012/7716

► The bachelor´s thesis analyses individual methods of usage electron beam in an industrial practice, as a welding, machining, deposition, heat treatment material and gravure. As… (more)

Subjects/Keywords: Elektron; svazek; svařování; energie; laser; Electron; beam; welding; energy; laser

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APA (6^th Edition):

Rudyk, M. (2019). Analýza aplikací svazku elektronů v průmyslu: Analysis of application electron beam in industry. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/7716

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Rudyk, Martin. “Analýza aplikací svazku elektronů v průmyslu: Analysis of application electron beam in industry.” 2019. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/7716.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Rudyk, Martin. “Analýza aplikací svazku elektronů v průmyslu: Analysis of application electron beam in industry.” 2019. Web. 09 Mar 2021.

Vancouver:

Rudyk M. Analýza aplikací svazku elektronů v průmyslu: Analysis of application electron beam in industry. [Internet] [Thesis]. Brno University of Technology; 2019. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/7716.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rudyk M. Analýza aplikací svazku elektronů v průmyslu: Analysis of application electron beam in industry. [Thesis]. Brno University of Technology; 2019. Available from: http://hdl.handle.net/11012/7716

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Brno University of Technology

16. Roščák, Michal. Návrh optické soustavy na rozšíření svazku Nd:YAG laseru v aparatuře pro laserovou spektroskopii (LIBS): Design of an optical system for expanding of the Nd:YAG laser beam in the Laser Induced Breakdown Spectroscopy (LIBS) setup.

Degree: 2019, Brno University of Technology

URL: http://hdl.handle.net/11012/14881

► Purpose of this bachelor thesis is to design of an telescope for expanding the Nd:YAG laser gauss beam used in LIBS aparature. Intesity of the… (more)

Subjects/Keywords: Laser; LIBS; ďalekohžad; gaussovský zväzok; Laser; LIBS; telescope; gauss beam

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APA (6^th Edition):

Roščák, M. (2019). Návrh optické soustavy na rozšíření svazku Nd:YAG laseru v aparatuře pro laserovou spektroskopii (LIBS): Design of an optical system for expanding of the Nd:YAG laser beam in the Laser Induced Breakdown Spectroscopy (LIBS) setup. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/14881

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Roščák, Michal. “Návrh optické soustavy na rozšíření svazku Nd:YAG laseru v aparatuře pro laserovou spektroskopii (LIBS): Design of an optical system for expanding of the Nd:YAG laser beam in the Laser Induced Breakdown Spectroscopy (LIBS) setup.” 2019. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/14881.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Roščák, Michal. “Návrh optické soustavy na rozšíření svazku Nd:YAG laseru v aparatuře pro laserovou spektroskopii (LIBS): Design of an optical system for expanding of the Nd:YAG laser beam in the Laser Induced Breakdown Spectroscopy (LIBS) setup.” 2019. Web. 09 Mar 2021.

Vancouver:

Roščák M. Návrh optické soustavy na rozšíření svazku Nd:YAG laseru v aparatuře pro laserovou spektroskopii (LIBS): Design of an optical system for expanding of the Nd:YAG laser beam in the Laser Induced Breakdown Spectroscopy (LIBS) setup. [Internet] [Thesis]. Brno University of Technology; 2019. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/14881.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Roščák M. Návrh optické soustavy na rozšíření svazku Nd:YAG laseru v aparatuře pro laserovou spektroskopii (LIBS): Design of an optical system for expanding of the Nd:YAG laser beam in the Laser Induced Breakdown Spectroscopy (LIBS) setup. [Thesis]. Brno University of Technology; 2019. Available from: http://hdl.handle.net/11012/14881

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Brno University of Technology

17. Kolkop, David. Technologie řezání laserem: Technology of Laser Cutting.

Degree: 2014, Brno University of Technology

URL: http://hdl.handle.net/11012/12197

► This diploma thesis treats about technology of laser and its use in practice. It describes principle, available types and possible applications in material working. The… (more)

Subjects/Keywords: laser; řezání; Byspeed; technologie; paprsek; laser; cutting; Byspeed; technology; beam

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APA (6^th Edition):

Kolkop, D. (2014). Technologie řezání laserem: Technology of Laser Cutting. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/12197

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kolkop, David. “Technologie řezání laserem: Technology of Laser Cutting.” 2014. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/12197.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kolkop, David. “Technologie řezání laserem: Technology of Laser Cutting.” 2014. Web. 09 Mar 2021.

Vancouver:

Kolkop D. Technologie řezání laserem: Technology of Laser Cutting. [Internet] [Thesis]. Brno University of Technology; 2014. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/12197.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kolkop D. Technologie řezání laserem: Technology of Laser Cutting. [Thesis]. Brno University of Technology; 2014. Available from: http://hdl.handle.net/11012/12197

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

18. Zohrabi, Mohammad. Quantum control of molecular fragmentation in strong laser field.

Degree: PhD, Department of Physics, 2014, Kansas State University

URL: http://hdl.handle.net/2097/18401

► Present advances in laser technology allow the production of ultrashort (≲5 fs, approaching single cycle at 800 nm), intense tabletop laser pulses. At these high… (more)

▼ Present advances in laser technology allow the production of ultrashort (≲5 fs, approaching single cycle at 800 nm), intense tabletop laser pulses. At these high intensities laser-matter interactions cannot be described with perturbation theory since multiphoton processes are involved. This is in contrast to photodissociation by the absorption of a single photon, which is well described by perturbation theory. For example, at high intensities (≳5×10[superscript]13 W/cm[superscript]2) the fragmentation of molecular hydrogen ions has been observed via the absorption of three or more photons. In another example, an intriguing dissociation mechanism has been observed where molecular hydrogen ions seem to fragment by apparently absorbing no photons. This is actually a two photon process, photoabsorption followed by stimulated emission, resulting in low energy fragments. We are interested in exploring these kinds of multiphoton processes. Our research group has studied the dynamics and control of fragmentation induced by strong laser fields in a variety of molecular targets. The main goal is to provide a basic understanding of fragmentation mechanisms and possible control schemes of benchmark systems such as H[subscript]2[superscript]+. This knowledge is further extended to more complex systems like the benchmark H[subscript]3[superscript]+ polyatomic and other molecules. In this dissertation, we report research based on two types of experiments. In the first part, we describe laser-induced fragmentation of molecular ion-beam targets. In the latter part, we discuss the formation of highly-excited neutral fragments from hydrogen molecules using ultrashort laser pulses. In carrying out these experiments, we have also extended experimental techniques beyond their previous capabilities. We have performed a few experiments to advance our understanding of laser-induced fragmentation of molecular-ion beams. For instance, we explored vibrationally resolved spectra of O[subscript]2[superscript]+ dissociation using various wavelengths. We observed a vibrational suppression effect in the dissociation spectra due to the small magnitude of the dipole transition moment, which depends on the photon energy – a phenomenon known as Cooper minima. By changing the laser wavelength, the Cooper minima shift, a fact that was used to identify the dissociation pathways. In another project, we studied the carrier-envelope phase (CEP) dependences of highly-excited fragments from hydrogen molecules. General CEP theory predicts a CEP dependence in the total dissociation yield due to the interference of dissociation pathways differing by an even net number of photons, and our measurements are consistent with this prediction. Moreover, we were able to extract the difference in the net number of photons involved in the interfering pathways by using a Fourier analysis. In terms of our experimental method, we have implemented a pump-probe style technique on a thin molecular ion-beam target and explored the feasibility of such experiments. The results… Advisors/Committee Members: Itzhak Ben-Itzhak.

Subjects/Keywords: Ultrafast laser studies, Molecular-ion beam, Strong field laser studies, Dissociation; Molecular-ion beam; Strong field laser studies; Dissociation; Physics (0605)

7 more images…

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APA (6^th Edition):

Zohrabi, M. (2014). Quantum control of molecular fragmentation in strong laser field. (Doctoral Dissertation). Kansas State University. Retrieved from http://hdl.handle.net/2097/18401

Chicago Manual of Style (16^th Edition):

Zohrabi, Mohammad. “Quantum control of molecular fragmentation in strong laser field.” 2014. Doctoral Dissertation, Kansas State University. Accessed March 09, 2021. http://hdl.handle.net/2097/18401.

MLA Handbook (7^th Edition):

Zohrabi, Mohammad. “Quantum control of molecular fragmentation in strong laser field.” 2014. Web. 09 Mar 2021.

Vancouver:

Zohrabi M. Quantum control of molecular fragmentation in strong laser field. [Internet] [Doctoral dissertation]. Kansas State University; 2014. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/2097/18401.

Council of Science Editors:

Zohrabi M. Quantum control of molecular fragmentation in strong laser field. [Doctoral Dissertation]. Kansas State University; 2014. Available from: http://hdl.handle.net/2097/18401

Brno University of Technology

19. Šustr, Michal. Laserový paprsek ve strojírenství: A laser beam in engineering.

Degree: 2020, Brno University of Technology

URL: http://hdl.handle.net/11012/195386

► The bachelor thesis focuses on the use of laser beam in the conditions of contemporary engineering, especially in cutting. Emphasis is put on the current… (more)

Subjects/Keywords: laser; laserový paprsek; obrábění laserem; nekonvenční technologie; laserové řezání; laser; laser beam; laser machining; unconventional technology; laser cutting

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APA (6^th Edition):

Šustr, M. (2020). Laserový paprsek ve strojírenství: A laser beam in engineering. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/195386

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Šustr, Michal. “Laserový paprsek ve strojírenství: A laser beam in engineering.” 2020. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/195386.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Šustr, Michal. “Laserový paprsek ve strojírenství: A laser beam in engineering.” 2020. Web. 09 Mar 2021.

Vancouver:

Šustr M. Laserový paprsek ve strojírenství: A laser beam in engineering. [Internet] [Thesis]. Brno University of Technology; 2020. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/195386.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Šustr M. Laserový paprsek ve strojírenství: A laser beam in engineering. [Thesis]. Brno University of Technology; 2020. Available from: http://hdl.handle.net/11012/195386

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Brno University of Technology

20. Kučera, Václav. Studium vlivu procesních parametrů na drsnost řezu při tavném režimu laserového dělení austenitické korozivzdorné oceli: The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel.

Degree: 2019, Brno University of Technology

URL: http://hdl.handle.net/11012/60185

► Thesis presents a study of the influence of process parameters on the roughness of the cut surface. The test material is 1.4301, namely austenitic stainless… (more)

Subjects/Keywords: Laser; řezání; drsnost; procesní parametry; laserový paprsek; Laser; cutting; roughness; processing parameters; the laser beam

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kučera, V. (2019). Studium vlivu procesních parametrů na drsnost řezu při tavném režimu laserového dělení austenitické korozivzdorné oceli: The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/60185

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kučera, Václav. “Studium vlivu procesních parametrů na drsnost řezu při tavném režimu laserového dělení austenitické korozivzdorné oceli: The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel.” 2019. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/60185.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kučera, Václav. “Studium vlivu procesních parametrů na drsnost řezu při tavném režimu laserového dělení austenitické korozivzdorné oceli: The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel.” 2019. Web. 09 Mar 2021.

Vancouver:

Kučera V. Studium vlivu procesních parametrů na drsnost řezu při tavném režimu laserového dělení austenitické korozivzdorné oceli: The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel. [Internet] [Thesis]. Brno University of Technology; 2019. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/60185.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kučera V. Studium vlivu procesních parametrů na drsnost řezu při tavném režimu laserového dělení austenitické korozivzdorné oceli: The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel. [Thesis]. Brno University of Technology; 2019. Available from: http://hdl.handle.net/11012/60185

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

21. Pinto, Regiane de Souza. Laser de Nd:YAG de alta potência, estabilidade e qualidade de feixe.

Degree: Mestrado, Tecnologia Nuclear - Materiais, 2014, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/85/85134/tde-04092014-145713/ ;

►

O trabalho experimental aqui apresentado tem como foco o desenvolvimento de um laser de estado sólido cujo desempenho foi otimizado de tal forma que contemple… (more)

▼

O trabalho experimental aqui apresentado tem como foco o desenvolvimento de um laser de estado sólido cujo desempenho foi otimizado de tal forma que contemple alta potência, alta qualidade de feixe e estabilidade, levando-se em conta os efeitos térmicos sofridos pelo meio ativo em regime de alta potência de bombeamento. Foram testadas cavidades para operação contínua em multimodo com alta potência de saída e cavidades operando em modo único TEM00. Para cavidades operando no modo fundamental, os ressonadores testados serão divididos em grupos de acordo com o seu comportamento no diagrama de estabilidade. A otimização de tais ressonadores foi realizada apenas alterando-se o raio de curvatura dos espelhos de entrada e saída e suas respectivas distâncias ao plano principal do bastão de Nd:YAG. Como resultado foi alcançada a maior eficiência de extração reportada na literatura para um ou dois módulos de Nd:YAG intracavidade. Os resultados dão uma visão geral sobre possíveis projetos de ressonadores para operação dinamicamente estável, com alta potência de saída e qualidade de feixe. Os dados obtidos servem como base para o desenvolvimento de novos lasers de alta potência e eficiência baseados em módulos DPSSL (Diode-Pumped Solid-State Lasers- Lasers de Estado Sólido Bombeados por Diodo) de baixo custo.

The experimental work presented here focuses on the development of a solid-state laser whose performance has been optimized for high power output, high beam quality, and high stability, taking into account the thermal effects experienced by the gain medium under high pumping power. Cavities for continuous wave (CW) operation in multimode with high output power and cavities operating in single mode TEM00 were tested. The resonators will be divided in groups according to their stability diagram. The optimization of such resonators was performed only by changing the curvature radius of the mirrors and their distances to the principal plane of the Nd:YAG rod. As a result was achieved the highest extraction efficiency reported in the literature for one or two intra cavity Nd:YAG modules. The results give an overview of possible designs of resonators for dynamically stable operation with high output power and beam quality. The data serve as basis for the development of new high-power lasers based on low cost DPSSL modules.

Advisors/Committee Members: Wetter, Niklaus Ursus.

Subjects/Keywords: beam quality; laser; laser; laser de estado sólido; Nd:YAG; Nd:YAG; qualidade de feixe; solid-state laser

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Pinto, R. d. S. (2014). Laser de Nd:YAG de alta potência, estabilidade e qualidade de feixe. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/85/85134/tde-04092014-145713/ ;

Chicago Manual of Style (16^th Edition):

Pinto, Regiane de Souza. “Laser de Nd:YAG de alta potência, estabilidade e qualidade de feixe.” 2014. Masters Thesis, University of São Paulo. Accessed March 09, 2021. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-04092014-145713/ ;.

MLA Handbook (7^th Edition):

Pinto, Regiane de Souza. “Laser de Nd:YAG de alta potência, estabilidade e qualidade de feixe.” 2014. Web. 09 Mar 2021.

Vancouver:

Pinto RdS. Laser de Nd:YAG de alta potência, estabilidade e qualidade de feixe. [Internet] [Masters thesis]. University of São Paulo; 2014. [cited 2021 Mar 09]. Available from: http://www.teses.usp.br/teses/disponiveis/85/85134/tde-04092014-145713/ ;.

Council of Science Editors:

Pinto RdS. Laser de Nd:YAG de alta potência, estabilidade e qualidade de feixe. [Masters Thesis]. University of São Paulo; 2014. Available from: http://www.teses.usp.br/teses/disponiveis/85/85134/tde-04092014-145713/ ;

Brno University of Technology

22. Hruška, Daniel. Aplikace CNC pro řezání laserem: CNC Applications for Laser Cutting.

Degree: 2020, Brno University of Technology

URL: http://hdl.handle.net/11012/192195

► The following thesis deals with the theory of laser. In the first part, the thesis is focused on the issue of laser cutting (laser principle,… (more)

Subjects/Keywords: řezání laserem; laser; laserový paprsek; automatizace; CNC stroj; laser cutting; laser; laser beam; automation; CNC machine

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hruška, D. (2020). Aplikace CNC pro řezání laserem: CNC Applications for Laser Cutting. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/192195

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hruška, Daniel. “Aplikace CNC pro řezání laserem: CNC Applications for Laser Cutting.” 2020. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/192195.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hruška, Daniel. “Aplikace CNC pro řezání laserem: CNC Applications for Laser Cutting.” 2020. Web. 09 Mar 2021.

Vancouver:

Hruška D. Aplikace CNC pro řezání laserem: CNC Applications for Laser Cutting. [Internet] [Thesis]. Brno University of Technology; 2020. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/192195.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hruška D. Aplikace CNC pro řezání laserem: CNC Applications for Laser Cutting. [Thesis]. Brno University of Technology; 2020. Available from: http://hdl.handle.net/11012/192195

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Brno University of Technology

23. Golda, Martin. Top hat svazek v optických bezkabelových spojích: Top hat beam in free space optics.

Degree: 2018, Brno University of Technology

URL: http://hdl.handle.net/11012/6788

► This thesis describes a way of laser beam shaping of Gaussian profile to Top hat profile and the influence of atmospheric turbulences and attenuation on… (more)

Subjects/Keywords: LED; laser; optický svazek; tvarování laserového paprsku; Top hat; Gausův svazek; atmosférické turbulence; atmosférický útlum.; LED; laser; optical beam; laser beam shaping; Top hat; Gaussian beam; atmospheric turbulences; atmospheric attenuation.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Golda, M. (2018). Top hat svazek v optických bezkabelových spojích: Top hat beam in free space optics. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/6788

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Golda, Martin. “Top hat svazek v optických bezkabelových spojích: Top hat beam in free space optics.” 2018. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/6788.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Golda, Martin. “Top hat svazek v optických bezkabelových spojích: Top hat beam in free space optics.” 2018. Web. 09 Mar 2021.

Vancouver:

Golda M. Top hat svazek v optických bezkabelových spojích: Top hat beam in free space optics. [Internet] [Thesis]. Brno University of Technology; 2018. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/6788.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Golda M. Top hat svazek v optických bezkabelových spojích: Top hat beam in free space optics. [Thesis]. Brno University of Technology; 2018. Available from: http://hdl.handle.net/11012/6788

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

24. Maximo, Henry Wilson Pohling. Avaliação de propriedades mecânicas e microestruturais de juntas de aços maraging soldadas por meio dos processos laser e feixe de elétrons.

Degree: Mestrado, Tecnologia Nuclear - Materiais, 2014, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/85/85134/tde-27052015-090049/ ;

►

Neste trabalho estudou-se as propriedades obtidas em juntas soldadas pelo processo de soldagem a laser do tipo estado sólido de onda contínua guiado por fibra,… (more)

▼

Neste trabalho estudou-se as propriedades obtidas em juntas soldadas pelo processo de soldagem a laser do tipo estado sólido de onda contínua guiado por fibra, e os resultados foram comparados com juntas soldadas pelo processo feixe de elétrons. O material utilizado foi o aço maraging 350 - ASTM A 538 Grade C. As soldas realizadas com o processo feixe de elétrons possuem um procedimento de soldagem aprovado. A junta selecionada para a elaboração do trabalho foi do tipo sobreposta com material de base de espessuras diferentes, respectivamente iguais a 1,00 e 0,78 mm. As juntas soldadas foram avaliadas por: ensaio de cisalhamento, dureza Vickers e caracterização microestrutural das diversas regiões das juntas soldadas. Foram realizadas análises por microscopia óptica e microscopia eletrônica de varredura usando espectrometria de energia dispersiva (MEV/EDS). Foi realizado o teste de hipótese como técnica para a análise dos dados provenientes dos ensaios experimentais. Nas juntas soldadas com ambos processos não foi verificada a presença de descontinuidades, poros e depressões na superfície do cordão. Os resultados indicam que as condições usadas em ambos os processos de soldagem foram satisfatórias e possibilitaram a soldagem do aço maraging 350 atendendo aos requisitos necessários.

In this work, the welds made by a continuous wave diode pumped solid state laser guided by fiber were studied and the results were compared with welded joints of electron beam welding. The material used was maraging 350 steel ASTM A 538 Grade C. The welding process performed with electron beam welding has a approved welding procedure. The joint chosen for the preparation of the work was the lap joint type with different thicknesses base material respectively equal to 1,00 and 0,78 mm. The welded joints were evaluated by mechanical tests like shear test, Vickers hardness and microstructural characterization of the various regions of the welded joints. Analyzes were performed by optical microscopy and scanning electron microscopy using energy dispersive spectrometry (SEM/EDS). The hypothesis test technique was done for the analysis of data from experimental tests. For both welding process was not detected in the welded joints the presence of discontinuities, pores and depressions on the weld fillet surface. The results indicate that the conditions used for both welding process were satisfactory and allowed the welding of maraging 350 steel meeting necessary requirements.

Advisors/Committee Members: Neves, Maurício David Martins das.

Subjects/Keywords: 350 maraging steel; electron beam welding; laser beam welding; maraging 350; soldagem a laser; soldagem por feixe de elétrons

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Maximo, H. W. P. (2014). Avaliação de propriedades mecânicas e microestruturais de juntas de aços maraging soldadas por meio dos processos laser e feixe de elétrons. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/85/85134/tde-27052015-090049/ ;

Chicago Manual of Style (16^th Edition):

Maximo, Henry Wilson Pohling. “Avaliação de propriedades mecânicas e microestruturais de juntas de aços maraging soldadas por meio dos processos laser e feixe de elétrons.” 2014. Masters Thesis, University of São Paulo. Accessed March 09, 2021. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-27052015-090049/ ;.

MLA Handbook (7^th Edition):

Maximo, Henry Wilson Pohling. “Avaliação de propriedades mecânicas e microestruturais de juntas de aços maraging soldadas por meio dos processos laser e feixe de elétrons.” 2014. Web. 09 Mar 2021.

Vancouver:

Maximo HWP. Avaliação de propriedades mecânicas e microestruturais de juntas de aços maraging soldadas por meio dos processos laser e feixe de elétrons. [Internet] [Masters thesis]. University of São Paulo; 2014. [cited 2021 Mar 09]. Available from: http://www.teses.usp.br/teses/disponiveis/85/85134/tde-27052015-090049/ ;.

Council of Science Editors:

Maximo HWP. Avaliação de propriedades mecânicas e microestruturais de juntas de aços maraging soldadas por meio dos processos laser e feixe de elétrons. [Masters Thesis]. University of São Paulo; 2014. Available from: http://www.teses.usp.br/teses/disponiveis/85/85134/tde-27052015-090049/ ;

25. Chougrani, Laurent. Modélisation avancée de formes complexes de pièces mécaniques pour lesprocédés de fabrication additive : Advanced modeling of complex mechanical structures for additive manufacturing.

Degree: Docteur es, Conception, 2017, Paris, ENSAM

URL: http://www.theses.fr/2017ENAM0054

►

Les procédés de fabrication additive ont connus un fort essor dans les dernières décennies et entament aujourd'hui leur phase d'industrialisation pérenne. L'industrie, dans un souci… (more)

▼

Les procédés de fabrication additive ont connus un fort essor dans les dernières décennies et entament aujourd'hui leur phase d'industrialisation pérenne. L'industrie, dans un souci d'améliorer sans cesse le ratio masse/rigidité des systèmes qu'elle produit (notamment l'industrie aéronautique), a pris conscience du potentiel de ces technologies à produire des structures plus complexes que les procédés classiques. Elle cherche aujourd'hui à tirer profit de ce potentiel pour alléger encore plus les pièces produites en utilisant notamment des géométries de type réseaux ou alvéolaires (Lattice en anglais). Les travaux présentés dans ce manuscrit ont pour but de proposer une méthodologie, des modèles et des outils permettant la conception, le dimensionnement et l'optimisation de telles structures en vue de leur fabrication par procédés additifs. Le framework proposé peut être résumé par les huit étapes ci-dessous:- Importation de l'espace de conception, comprenant également les cas de chargement.- Optimisation topologique sur l'espace de conception.- Reconstruction de la géométrie, appelée primitive, qui servira de support à l'insertion du réseau.- Calcul par éléments finis qui peut être réalisé pour s'assurer de la bonne tenue mécanique.- Définition de la topologie du réseau, par l'intermédiaire d'un graphe 3D.- Déformation du réseau et optimisation mécanique du réseau.- Reconstruction des volumes.- Préparation des fichiers de données et impression 3D.

Additive manufacturing processes have been quickly growing those past decades and are now getting to their sustainable industrial. Industry has been caring about the mass to rigidity ratio of the structures it produces (especially in aeronautics), and is now acknowledging the potential of additive processes to produce more complex shapes than classical processes. Industry is now trying to take advantage of this potential by designing highly complex structures like lattices or metal foams. The work that is presented in this document propose a methodology, models and numerical tools allowing the conception, dimensioning and optimization of such structures through additive manufacturing. The proposed framework can be describe through the height following steps:- Importing the design space and the technical requirement (load cases).- Topology optimization of the design space- Geometry reconstruction to create a primitive which will be the lattice insertion area.- Finite elements computation to ensure that the structure meets the requirements.- Lattice topology definition using 3D graphs.- Lattice deformation and optimization.- Creation of the volumes around the lattice.- Printing file creation and 3D printing.

Advisors/Committee Members: Veron, Philippe (thesis director), Pernot, Jean-Philippe (thesis director).

Subjects/Keywords: Fabrication additive; Optimisation; Structures alvéolaires; Fusion laser; Faisceau d'électrons; Additive manufacturing; Optimization; Lattice structures; Laser beam melting; Electron beam melting

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chougrani, L. (2017). Modélisation avancée de formes complexes de pièces mécaniques pour lesprocédés de fabrication additive : Advanced modeling of complex mechanical structures for additive manufacturing. (Doctoral Dissertation). Paris, ENSAM. Retrieved from http://www.theses.fr/2017ENAM0054

Chicago Manual of Style (16^th Edition):

Chougrani, Laurent. “Modélisation avancée de formes complexes de pièces mécaniques pour lesprocédés de fabrication additive : Advanced modeling of complex mechanical structures for additive manufacturing.” 2017. Doctoral Dissertation, Paris, ENSAM. Accessed March 09, 2021. http://www.theses.fr/2017ENAM0054.

MLA Handbook (7^th Edition):

Chougrani, Laurent. “Modélisation avancée de formes complexes de pièces mécaniques pour lesprocédés de fabrication additive : Advanced modeling of complex mechanical structures for additive manufacturing.” 2017. Web. 09 Mar 2021.

Vancouver:

Chougrani L. Modélisation avancée de formes complexes de pièces mécaniques pour lesprocédés de fabrication additive : Advanced modeling of complex mechanical structures for additive manufacturing. [Internet] [Doctoral dissertation]. Paris, ENSAM; 2017. [cited 2021 Mar 09]. Available from: http://www.theses.fr/2017ENAM0054.

Council of Science Editors:

Chougrani L. Modélisation avancée de formes complexes de pièces mécaniques pour lesprocédés de fabrication additive : Advanced modeling of complex mechanical structures for additive manufacturing. [Doctoral Dissertation]. Paris, ENSAM; 2017. Available from: http://www.theses.fr/2017ENAM0054

26. Carvalho, Sheila Medeiros de. Estudo da soldabilidade a laser e a TIG do titânio comercialmente puro grau 2 empregado em sistemas pneumáticos de aeronaves.

Degree: PhD, Materiais Metálicos, Cerâmicos e Poliméricos, 2012, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/97/97134/tde-02102013-112909/ ;

►

O conjunto de tubos denominado sistema pneumático, tem a função de conduzir o ar quente pressurizado desde o motor até os pontos de utilização pelos… (more)

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O conjunto de tubos denominado sistema pneumático, tem a função de conduzir o ar quente pressurizado desde o motor até os pontos de utilização pelos sistemas ambientais da aeronave. A ocorrência de falhas em serviço de peças desse sistema soldadas pelo processo TIG (Tungsten Inert Gas), motivou o estudo da substituição desse processo pelo de soldagem a laser. Foi utilizado um laser a fibra de 2 kW de potência e tubos de titânio comercialmente puro grau 2, de 0,5 mm de espessura e 50 mm de diâmetro. Para efeito de comparação foram realizadas soldas pelo processo TIG, semi-automático, cujos parâmetros foram obtidos junto a uma empresa fabricante de aviões. Os tubos de titânio foram soldados em cheio, sem adição de arame, e o argônio foi utilizado como gás de proteção. Os parâmetros de soldagem a laser selecionados foram 200 W e 2000 mm/min e, 250 W e 300 mm/min. Os tubos soldados a laser apresentam cordões com aproximadamente 1 mm de largura e grãos de Ti-CP ?, enquanto que as soldas TIG resultam em cordões de 5 mm e grãos grosseiros serrilhado de Ti-CP ?. O refinamento microestrutural observado nas amostras soldadas a laser, em relação à TIG, deve-se a alta taxa de resfriamento, que no laser foi cerca de 70 vezes maior do que no TIG. Os tubos soldados a laser e TIG foram ciclados na bancada pneumática, 44.000 vezes, a 350 °C, sem fraturarem ou iniciarem uma trinca que comprometesse os testes de pressurização cíclica. Os resultados de fadiga evidenciaram uma maior resistência mecânica da solda a laser na condição de 200 W e 2000 mm/min, quando comparado com as demais condições de soldagem. As avaliações microestruturais e mecânicas dos cordões de solda evidenciaram as vantagens do processo de soldagem a laser para substituir o TIG, em junções do sistema pneumático de aeronaves.

The engine bleed air system, also known as pneumatic system, conducts the pressurized hot air from the engine to the environmental systems of aircrafts. In-service failures of the arc welded pneumatic parts have driven further developments of laser beam welding as an alternative method. Here, a fiber laser with 2 kW power had been employed to weld commercial purity titanium alloy tubes with 0.5 wall thickness and 50 mm diameter. For comparison purposes, semiautomatic TIG welding was realized, based on the previous experience of an aircraft company. All the welds were autogenous, bead-on-plate, and under protective argon atmosphere. The chosen parameters speed and laser powers for laser welding were 200 W - 2000 mm/min and 250 W - 300 mm/min. The laser welded tubes presented 1-mm wide weld beads composed by grained ?-Ti. The TIG welded tubes showed 5-mm wide beads composed by acicular ?-Ti grains. These observed differences had been associated to the cooling rate, which is seventy times higher in the laser case. Both laser and TIG welded tubes were cycled 44.000 times in a pneumatic bench at 350 °C without failures or cracks that could break the internal pressure. The condition 200W-2000mm/min presented superior fatigue resistance values…

Advisors/Committee Members: Baptista, Carlos Antonio Reis Pereira.

Subjects/Keywords: Fadiga; Fatigue; Laser beam welding; Soldagem a laser; Soldagem TIG; TIG welding; Titânio; Titanium

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Carvalho, S. M. d. (2012). Estudo da soldabilidade a laser e a TIG do titânio comercialmente puro grau 2 empregado em sistemas pneumáticos de aeronaves. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/97/97134/tde-02102013-112909/ ;

Chicago Manual of Style (16^th Edition):

Carvalho, Sheila Medeiros de. “Estudo da soldabilidade a laser e a TIG do titânio comercialmente puro grau 2 empregado em sistemas pneumáticos de aeronaves.” 2012. Doctoral Dissertation, University of São Paulo. Accessed March 09, 2021. http://www.teses.usp.br/teses/disponiveis/97/97134/tde-02102013-112909/ ;.

MLA Handbook (7^th Edition):

Carvalho, Sheila Medeiros de. “Estudo da soldabilidade a laser e a TIG do titânio comercialmente puro grau 2 empregado em sistemas pneumáticos de aeronaves.” 2012. Web. 09 Mar 2021.

Vancouver:

Carvalho SMd. Estudo da soldabilidade a laser e a TIG do titânio comercialmente puro grau 2 empregado em sistemas pneumáticos de aeronaves. [Internet] [Doctoral dissertation]. University of São Paulo; 2012. [cited 2021 Mar 09]. Available from: http://www.teses.usp.br/teses/disponiveis/97/97134/tde-02102013-112909/ ;.

Council of Science Editors:

Carvalho SMd. Estudo da soldabilidade a laser e a TIG do titânio comercialmente puro grau 2 empregado em sistemas pneumáticos de aeronaves. [Doctoral Dissertation]. University of São Paulo; 2012. Available from: http://www.teses.usp.br/teses/disponiveis/97/97134/tde-02102013-112909/ ;

27. Santos, Moisés Oliveira dos. Desenvolvimento de um sistema automatizado para a caracterização espacial de feixes lasers.

Degree: Mestrado, Física Aplicada à Medicina e Biologia, 2007, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-13032008-143339/ ;

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A demanda por qualidade nas aplicações envolvendo radiação laser exigiu melhorias no seu desempenho. Conseqüentemente, equipamentos mais rápidos e precisos nas medidas dos seus parâmetros… (more)

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A demanda por qualidade nas aplicações envolvendo radiação laser exigiu melhorias no seu desempenho. Conseqüentemente, equipamentos mais rápidos e precisos nas medidas dos seus parâmetros são indispensáveis. Nas áreas onde o laser é empregado, três parâmetros sobressaem-se nas suas aplicações: (1) potência ou energia, (2) freqüência e (3) comprimento espacial ou largura do feixe. A determinação das bordas, isto é, da largura do feixe, está ligada a um percentual do máximo valor atingido pela energia. O diâmetro do feixe, juntamente com a energia, determina-se a densidade do feixe. Outros parâmetros como: divergência e fator de qualidade (M2), podem ser determinados também. O presente trabalho busca desenvolver um sistema de translação bidimensional que possa ser empregado na caracterização espacial do feixe de lasers. Para determinar o perfil do feixe de lasers utiliza-se o método borda-da-lâmina (knife-edge), relacionando o deslocamento da lâmina posicionada transversalmente ao feixe, com a energia transmitida. Obstruindo o feixe com uma lâmina opaca, obtêm-se a variação da energia do feixe em função da posição da lâmina. Esta variação representa a integral do perfil Gaussiano do feixe. Para a automação do sistema foi empregado o programa Labview (National Instruments). O funcionamento do protótipo mostrou-se eficiente na caracterização de feixes laser e com uma instrumentação de baixo custo para a comercialização nacional. No entanto, apresentou-se lento na aquisição de dados, tornando a tarefa de caracterização do laser mais demorada. Fatores como velocidade do motor de passo e linguagem de programação contribuíram para tornar a aquisição lenta.

The demand for quality in the applications involving laser radiation demanded improvements in its performance. Faster equipments in the measures of its parameters are indispensable. In the areas where the laser is employee, three parameters are important in its applications: (1) power or energy, (2) frequency and (3) beam spatial. The determination of the edges, i. e., the width of the beam, is correlated to a percentage of the maximum reached energy. This parameter, together with the energy, determines beam density; beyond this parameter it also possible to determine the divergence and quality factor (M2). This work searches to develop a system of bi-dimension translation that can be used in the spatial characterization of laser beam. To determine the profile of laser beam it is used the knife-edge method, that it relates the displacement of the blade located transversally to the beam, with the transmitted energy. Blocking the beam with a blade the energy variation of the beam is correlated with blade position; this variation represents the integral of the beam Gaussian profile. For the automation it will be used the Labview program(National Instruments). The prototype had showed to be efficient in the characterization of laser beams and a low cost for national commercialization; however was slow in the data acquisition resulting a longer time to acquire the laser…

Advisors/Committee Members: Bachmann, Luciano.

Subjects/Keywords: Beam Width; borda-da-lâmina e raio do feixe; Knife-edge; Laser; Laser

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Santos, M. O. d. (2007). Desenvolvimento de um sistema automatizado para a caracterização espacial de feixes lasers. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-13032008-143339/ ;

Chicago Manual of Style (16^th Edition):

Santos, Moisés Oliveira dos. “Desenvolvimento de um sistema automatizado para a caracterização espacial de feixes lasers.” 2007. Masters Thesis, University of São Paulo. Accessed March 09, 2021. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-13032008-143339/ ;.

MLA Handbook (7^th Edition):

Santos, Moisés Oliveira dos. “Desenvolvimento de um sistema automatizado para a caracterização espacial de feixes lasers.” 2007. Web. 09 Mar 2021.

Vancouver:

Santos MOd. Desenvolvimento de um sistema automatizado para a caracterização espacial de feixes lasers. [Internet] [Masters thesis]. University of São Paulo; 2007. [cited 2021 Mar 09]. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-13032008-143339/ ;.

Council of Science Editors:

Santos MOd. Desenvolvimento de um sistema automatizado para a caracterização espacial de feixes lasers. [Masters Thesis]. University of São Paulo; 2007. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-13032008-143339/ ;

Brno University of Technology

28. Strouhal, Lukáš. Technologie obrábění laserem: Technology of Laser Cutting.

Degree: 2020, Brno University of Technology

URL: http://hdl.handle.net/11012/192355

► The master’s thesis deals with laser cutting technology and application in the industry. The first part of the thesis describes principle of laser beam creation,… (more)

Subjects/Keywords: Laser; paprsek; vodní paprsek; řezání; obrábění; Laser; beam; water jet; cutting; machining

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Strouhal, L. (2020). Technologie obrábění laserem: Technology of Laser Cutting. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/192355

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Strouhal, Lukáš. “Technologie obrábění laserem: Technology of Laser Cutting.” 2020. Thesis, Brno University of Technology. Accessed March 09, 2021. http://hdl.handle.net/11012/192355.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Strouhal, Lukáš. “Technologie obrábění laserem: Technology of Laser Cutting.” 2020. Web. 09 Mar 2021.

Vancouver:

Strouhal L. Technologie obrábění laserem: Technology of Laser Cutting. [Internet] [Thesis]. Brno University of Technology; 2020. [cited 2021 Mar 09]. Available from: http://hdl.handle.net/11012/192355.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Strouhal L. Technologie obrábění laserem: Technology of Laser Cutting. [Thesis]. Brno University of Technology; 2020. Available from: http://hdl.handle.net/11012/192355

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

29. Saucourt, Jérémy. Nouveau procédé dynamique d’analyse et de contrôle du front d’onde synthétique de réseaux de lasers : New dynamical process for analysis and phase control of the synthetic wavefront of a laser beam array.

Degree: Docteur es, Electronique des Hautes Fréquences, Photonique et Systèmes, 2019, Limoges

URL: http://www.theses.fr/2019LIMO0050

►

Des projets futuristes tels que la production d’énergie par fusion nucléaire, ou encore la navigation interstellaire par voiles solaires, requièrent l’utilisation d’une source de lumière… (more)

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Des projets futuristes tels que la production d’énergie par fusion nucléaire, ou encore la navigation interstellaire par voiles solaires, requièrent l’utilisation d’une source de lumière de luminance extrême. Dans l’objectif d’augmenter la luminance de sources lasers, mes travaux de thèse ont porté sur la combinaison cohérente de réseaux de lasers. Ils ont conduit au développement d’un nouveau procédé de contrôle compact du front d’onde de synthèse formé par le réseau de faisceaux lasers. Ce procédé permet de sculpter à façon la figure intensimétrique du champ lointain et donc de contrôler la distribution angulaire d’énergie émise par le réseau de faisceaux lasers. Le procédé développé utilise un module convertisseur phase/amplitude intégrant un élément diffuseur. Une méthode de mesure de la matrice de transfert d’un système optique a été développée pour caractériser ce module convertisseur de champ. A tout instant, le front d’onde de synthèse est estimé par une boucle numérique de recouvrement de phase basée sur un algorithme à projections alternées. Ce calcul approché permet d’ajuster progressivement les relations de phases du réseau de faisceaux lasers jusqu’au jeu de phases arbitraire souhaité. Le procédé permet le contrôle d’un front d’onde de synthèse en moins de 10 corrections de phases, quasi-indépendamment du nombre de faisceaux lasers à contrôler. Il est robuste aux défauts environnementaux et indépendant du jeu de phases initiales. J’ai démontré la compacité du système étudié en analysant et contrôlant une pupille de synthèse de 4 cm de côté, constituée de 16 faisceaux, à l’aide d’un module d’analyse mesurant seulement 30 cm. J’ai également montré expérimentalement le contrôle des phases de réseaux de 16 à 100 faisceaux lasers avec des erreurs résiduelles valant respectivement λ/30 et λ/20 rms. Les capacités de cette méthode peuvent être étendues au contrôle des ordres de Zernike supérieurs du front d’onde de synthèse, ou bien plus généralement pour mesurer directement le front d’onde d’un rayonnement cohérent.

Futuristic projects such as nuclear fusion power generation, or interstellar navigation by solar sails, require the use of a light source of extreme brightness. In order to increase the brightness of laser sources, my thesis work focused on the coherent beam combination of laser arrays. They led to the development of a new compact control process for the synthetic wavefront formed by the laser beam array. This process makes it possible to tailor the intensity pattern of the far field and thus control the angular distribution of energy emitted by the laser beam array. The process developed uses a phase/amplitude converter module with an integrated diffuser element. A method of measuring the transfer matrix of an optical system has been developed to characterize this field converter module. At any time, the synthetic wavefront is estimated by a phase recovery loop based on an alternating projections algorithm. This approximate calculation makes it possible to gradually adjust the phase…

Advisors/Committee Members: Desfarges-Berthelemot, Agnès (thesis director), Kermène, Vincent (thesis director).

Subjects/Keywords: Laser; Combinaison cohérente; Diffusion; Optimisation; Laser; Coherent beam combining; Scattering; Optimization; 621.366

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Saucourt, J. (2019). Nouveau procédé dynamique d’analyse et de contrôle du front d’onde synthétique de réseaux de lasers : New dynamical process for analysis and phase control of the synthetic wavefront of a laser beam array. (Doctoral Dissertation). Limoges. Retrieved from http://www.theses.fr/2019LIMO0050

Chicago Manual of Style (16^th Edition):

Saucourt, Jérémy. “Nouveau procédé dynamique d’analyse et de contrôle du front d’onde synthétique de réseaux de lasers : New dynamical process for analysis and phase control of the synthetic wavefront of a laser beam array.” 2019. Doctoral Dissertation, Limoges. Accessed March 09, 2021. http://www.theses.fr/2019LIMO0050.

MLA Handbook (7^th Edition):

Saucourt, Jérémy. “Nouveau procédé dynamique d’analyse et de contrôle du front d’onde synthétique de réseaux de lasers : New dynamical process for analysis and phase control of the synthetic wavefront of a laser beam array.” 2019. Web. 09 Mar 2021.

Vancouver:

Saucourt J. Nouveau procédé dynamique d’analyse et de contrôle du front d’onde synthétique de réseaux de lasers : New dynamical process for analysis and phase control of the synthetic wavefront of a laser beam array. [Internet] [Doctoral dissertation]. Limoges; 2019. [cited 2021 Mar 09]. Available from: http://www.theses.fr/2019LIMO0050.

Council of Science Editors:

Saucourt J. Nouveau procédé dynamique d’analyse et de contrôle du front d’onde synthétique de réseaux de lasers : New dynamical process for analysis and phase control of the synthetic wavefront of a laser beam array. [Doctoral Dissertation]. Limoges; 2019. Available from: http://www.theses.fr/2019LIMO0050

30. Neuville, Cedric. Etude expérimentale des effets multi-faisceaux sur l'instabilité de diffusion Brillouin stimulée : Experimental study of multiple-beam effects on the stimulated Brillouin scattering instability.

Degree: Docteur es, Physique, 2017, Université Paris-Saclay (ComUE)

URL: http://www.theses.fr/2017SACLX046

►

Les installations laser dimensionnées pour réaliser des expériences de fusion thermonucléaire par confinement inertiel laser utilisent de nombreux faisceaux laser pour répondre à des contraintes… (more)

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Les installations laser dimensionnées pour réaliser des expériences de fusion thermonucléaire par confinement inertiel laser utilisent de nombreux faisceaux laser pour répondre à des contraintes de symétrie d'irradiation et pour déposer suffisamment d'énergie dans la matière. Malheureusement, le croisement des faisceaux laser dans un plasma impactent leurs propagations. Quand un faisceau laser se propage dans un plasma, il peut se coupler aux ondes acoustiques ioniques et diffuser une fraction importante de son énergie par diffusion Brillouin stimulée. Aussi bien les niveaux que les directions de ces diffusions sont profondément modifiés lorsque les faisceaux laser se croisent. Ce manuscrit présente l'étude expérimentale de deux types de modification multi-faisceaux :- en utilisant la flexibilité de l'installation laser LULI2000 (Laboratoire d'Utilisation des Lasers Intenses, Palaiseau, France), nous avons étudié le transfert d'énergie entre deux et trois faisceaux laser ;- les soixante faisceaux laser de l'installation OMEGA (Laboratory for Laser Energetics, Rochester, Etats-Unis) nous ont permis d'observer les diffusions produites par des instabilités Brillouin collectives dans des plasmas plans en géométrie ouverte et à l'entrée de cavités d'expériences de fusion.Ces deux mécanismes peuvent drastiquement redistribuer l'énergie laser incidente en échangeant jusqu’à 30% de l'énergie entre les faisceaux ou en diffusant plus de 10% de l'énergie laser dans des directions inhabituelles.

The laser facilities designed to realize laser inertial confinement thermonuclear fusion experiments use numerous laser beams in order to meet irradiation symmetry constraints and to deposite enough energy in matter. Unfortunately, the crossing of laser beams in plasmas modifies their propagations. When a beam is propagating in plasmas, it can interact with ion acoustic waves and scatter its energy by stimulated Brillouin scattering. Not only the directions but also the levels of these scatterings are modified when beams are crossing one another in plasmas. This manuscript is about the experimental study of two kinds of multiple-beam modification:- the flexibility of the LULI2000 laser facility (Laboratoire d'Utilisation de Lasers Intenses, Palaiseau, France) enabled us to study crossed-beam energy transfer between two and three beams;- the sixty laser beams available on the OMEGA facility (Laboratory for Laser Energetics, Rochester, United-States) enabled us to observe scattering of collective Brillouin instabilities produced in planar geometries and at the entrance hole of cavities of fusion experiments.These two mecanisms can highly modify the initial laser irradiation by transferring up to 30% of the laser energy between beams and by scattering more than 10% of the laser energy in unusual directions.

Advisors/Committee Members: Labaune, Christine (thesis director), Depierreux, Sylvie (thesis director).

Subjects/Keywords: Expérimentale; Laser; Plasma; Interaction; Croisement de faisceaux; Experimental; Laser; Plasma; Interaction; Beam crossing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Neuville, C. (2017). Etude expérimentale des effets multi-faisceaux sur l'instabilité de diffusion Brillouin stimulée : Experimental study of multiple-beam effects on the stimulated Brillouin scattering instability. (Doctoral Dissertation). Université Paris-Saclay (ComUE). Retrieved from http://www.theses.fr/2017SACLX046

Chicago Manual of Style (16^th Edition):

Neuville, Cedric. “Etude expérimentale des effets multi-faisceaux sur l'instabilité de diffusion Brillouin stimulée : Experimental study of multiple-beam effects on the stimulated Brillouin scattering instability.” 2017. Doctoral Dissertation, Université Paris-Saclay (ComUE). Accessed March 09, 2021. http://www.theses.fr/2017SACLX046.

MLA Handbook (7^th Edition):

Neuville, Cedric. “Etude expérimentale des effets multi-faisceaux sur l'instabilité de diffusion Brillouin stimulée : Experimental study of multiple-beam effects on the stimulated Brillouin scattering instability.” 2017. Web. 09 Mar 2021.

Vancouver:

Neuville C. Etude expérimentale des effets multi-faisceaux sur l'instabilité de diffusion Brillouin stimulée : Experimental study of multiple-beam effects on the stimulated Brillouin scattering instability. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); 2017. [cited 2021 Mar 09]. Available from: http://www.theses.fr/2017SACLX046.

Council of Science Editors:

Neuville C. Etude expérimentale des effets multi-faisceaux sur l'instabilité de diffusion Brillouin stimulée : Experimental study of multiple-beam effects on the stimulated Brillouin scattering instability. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); 2017. Available from: http://www.theses.fr/2017SACLX046

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Open Access Theses and Dissertations