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You searched for +publisher:"University of Notre Dame" +contributor:("Gregory V. Hartland, Research Director"). Showing records 1 – 3 of 3 total matches.

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University of Notre Dame

1. Tuphan Devkota. Optical Absorption-Based Studies of Single Nanostructures</h1>.

Degree: Chemistry and Biochemistry, 2019, University of Notre Dame

Spatial modulation spectroscopy (SMS) has been used to image single organic nanoparticles doped with non-fluorescent, near-IR croconaine dyes. Based on the measured extinction cross-section of the nanoparticles, the number of dye molecules per particle has been determined. SMS images were recorded for particles within EMT-6 breast cancer cells which allowed mapping of the nanoparticle location and the amount of dye in a single cell. This demonstrates how SMS can facilitate efforts to optimize dye-doped nanoparticles for effective photothermal treatment of cancer. SMS imaging has been extended to particles with sizes comparable to or larger than the laser spot, where the shape of the particle matters. <span></span>The mechanical resonances of metal nanostructures are strongly affected by their environment. Ultrafast pump-probe microscopy experiments has been used to study damping of the breathing mode vibrations of single gold nanowires by liquids with different viscosities. The measured quality factors for liquid damping are in good agreement with continuum mechanics calculations for an inviscid fluid showing that liquid damping is controlled by radiation of sound waves into the medium. Transient absorption microscopy (TAM) measurements have been used to study the optical properties of surface plasmon polariton (SPP) modes in gold nanoplates on a glass. The TAM images show an oscillation in the signal across the nanoplate due to interference between the bound and leaky SPP modes. Back focal plane (BFP) imaging was used to measure the wavevector of the leaky mode. By combining the results from two techniques, the wavevector of the bound mode has been determined. These experiments represent the first far-field optical measurement of the wavevector for the bound mode in metal nanostructures. Femtosecond laser excitation of strongly absorbing thin films generates picosecond acoustic waves in the surrounding medium. In time-domain transient absorption experiments these waves can give rise to Brillouin oscillations. The attenuation of the oscillations has been investigated for different excitation and detection conditions. The results show that the measured attenuation constants strongly depend on the numerical aperture of the microscope objective used. These results are important for understanding the spectral resolution limits in imaging applications of the Brillouin scattering effect.<span></span> Advisors/Committee Members: Gregory V. Hartland, Research Director.

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

APA (6th Edition):

Devkota, T. (2019). Optical Absorption-Based Studies of Single Nanostructures</h1>. (Thesis). University of Notre Dame. Retrieved from https://curate.nd.edu/show/cf95j96309w

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

Chicago Manual of Style (16th Edition):

Devkota, Tuphan. “Optical Absorption-Based Studies of Single Nanostructures</h1>.” 2019. Thesis, University of Notre Dame. Accessed July 02, 2020. https://curate.nd.edu/show/cf95j96309w.

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

MLA Handbook (7th Edition):

Devkota, Tuphan. “Optical Absorption-Based Studies of Single Nanostructures</h1>.” 2019. Web. 02 Jul 2020.

Vancouver:

Devkota T. Optical Absorption-Based Studies of Single Nanostructures</h1>. [Internet] [Thesis]. University of Notre Dame; 2019. [cited 2020 Jul 02]. Available from: https://curate.nd.edu/show/cf95j96309w.

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

Council of Science Editors:

Devkota T. Optical Absorption-Based Studies of Single Nanostructures</h1>. [Thesis]. University of Notre Dame; 2019. Available from: https://curate.nd.edu/show/cf95j96309w

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


University of Notre Dame

2. Paul Johns. Surface Plasmon Polaritons in Gold Nanostructures: Conversion, Coupling, and Confinement</h1>.

Degree: Chemistry and Biochemistry, 2017, University of Notre Dame

Gold nanostructures have found use in molecular sensing, logic functions, and nanocircuitry through the propagation of surface plasmon polariton (SPP) modes. Despite SPP usefulness, the effects of defects in the supporting substrate, the effects of defects in the nanostructures, and the effects of the geometry of nanostructures on the modes, the mode shapes, and various mode characteristics (such as damping as measured by propagation length) has not been well understood. Other key issues include coupling between nanostructures and the interactions of multiple SPP modes launched simultaneously. This dissertation clarifies some of these fundamental properties as exhibited primarily in gold nanowires through the use of pump-probe spectroscopy and computational modeling using COMSOL Multiphysics. Two primary SPP modes are studied: the bound mode, which propagates at the nanostructure/substrate interface, and the leaky mode, which propagates primarily at the nanostructure/air interface. SPPs are launched using end-fire coupling in which a laser is focused on the end of the nanostructure. When the field of the laser matches that of the plasmon field, SPPs are launched. Often multiple modes are launched simultaneously during an experiment, despite only one mode being of interest in a given experiment. The modes often have different properties and are affected differently by geometry and other factors in the system. Discontinuities in the supporting substrate result in the elimination of the bound mode while the leaky mode is retained. Nanowires that are cut in several places suffer 60 – 80% attenuation when cut widths range from 20 – 100 nm. Counter-intuitively, greater losses at are sustained at smaller gap sizes due to coupling to localized surface plasmon resonances, demonstrating a fundamental loss mechanism. Additionally, it is observed that as the lateral size of the nanowires increases, damping decreases. This is due to the reduced confinement of the mode at larger sizes, resulting in proportionally more of the field outside of the nanowire. Advisors/Committee Members: Zachary D. Schultz, Committee Member, Gregory V. Hartland, Research Director, Prashant V. Kamat, Committee Member.

Subjects/Keywords: gold; surface plasmon polariton; waveguides; COMSOL Multiphysics; finite element method; plasmonics; nanoscience; nanowires; transient absorption; nanoparticles

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

APA (6th Edition):

Johns, P. (2017). Surface Plasmon Polaritons in Gold Nanostructures: Conversion, Coupling, and Confinement</h1>. (Thesis). University of Notre Dame. Retrieved from https://curate.nd.edu/show/cr56n01256x

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

Chicago Manual of Style (16th Edition):

Johns, Paul. “Surface Plasmon Polaritons in Gold Nanostructures: Conversion, Coupling, and Confinement</h1>.” 2017. Thesis, University of Notre Dame. Accessed July 02, 2020. https://curate.nd.edu/show/cr56n01256x.

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

MLA Handbook (7th Edition):

Johns, Paul. “Surface Plasmon Polaritons in Gold Nanostructures: Conversion, Coupling, and Confinement</h1>.” 2017. Web. 02 Jul 2020.

Vancouver:

Johns P. Surface Plasmon Polaritons in Gold Nanostructures: Conversion, Coupling, and Confinement</h1>. [Internet] [Thesis]. University of Notre Dame; 2017. [cited 2020 Jul 02]. Available from: https://curate.nd.edu/show/cr56n01256x.

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

Council of Science Editors:

Johns P. Surface Plasmon Polaritons in Gold Nanostructures: Conversion, Coupling, and Confinement</h1>. [Thesis]. University of Notre Dame; 2017. Available from: https://curate.nd.edu/show/cr56n01256x

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


University of Notre Dame

3. Zhongming Li. Absorption-Based Spectroscopy and Microscopy on Nanostructures</h1>.

Degree: Chemistry and Biochemistry, 2017, University of Notre Dame

Spectroscopy and microscopy on nanostructures has been a heated research area for the past few decades. Among the different strategies, absorption-based techniques attracted a large amount of attention. Since absorption effect scales with volume while scattering effect scales with volume squared, for particles with sizes in the nanometer range, absorption is usually stronger than scattering. There are two techniques that are mainly discussed in this thesis, Spatial Modulation Spectroscopy (SMS) and Photothermal Heterodyne Imaging (PHI). In the first study, optical trapping was integrated with SMS to investigate the absorption behavior of gold nanoparticles in a homogenous aqueous environment at the single particle level. The linewidths of the absorption spectra were studied carefully and large electron-surface scattering effect was observed, possibly due to chemical interface damping. In the second studies, PHI was applied in the mid-infrared range so that the spatial resolution of mid-infrared imaging was improved by more than ten times, from the current state-of-the-art 5 mm to what was presented in this thesis of 0.3 mm. This mid-infrared photothermal imaging technique (MIR-PHI) has been demonstrated on a variety of soft matter systems, including polystyrene nanoparticles, photoresist polymer patterns, and single bacterium cells. High sensitivity (signal-to-noise >100) and flexible field-of-view (5 x 5 mm to 100 x 100 mm) was also achieved. In order to understand the fundamental mechanism that gives rise to the MIR-PHI signal, finite element analysis (FEA) was performed with Comsol Multiphysics. Simulations revealed that the two mechanisms that contribute to the overall signal, refractive index change and thermal expansion, counteract with each other. For polystyrene, refractive index change is more prominent than thermal expansion. Also, the medium effect that was the dominating effect in conventional photothermal experiments is not as important in this setting anymore, especially for the larger particles. MIR-PHI might find its potential in stain-free histology, as well as other biomedical applications. Advisors/Committee Members: Prashant V. Kamat, Committee Member, S. Alex Kandel, Committee Member, Gregory V. Hartland, Research Director.

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

APA (6th Edition):

Li, Z. (2017). Absorption-Based Spectroscopy and Microscopy on Nanostructures</h1>. (Thesis). University of Notre Dame. Retrieved from https://curate.nd.edu/show/2r36tx33r5j

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

Chicago Manual of Style (16th Edition):

Li, Zhongming. “Absorption-Based Spectroscopy and Microscopy on Nanostructures</h1>.” 2017. Thesis, University of Notre Dame. Accessed July 02, 2020. https://curate.nd.edu/show/2r36tx33r5j.

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

MLA Handbook (7th Edition):

Li, Zhongming. “Absorption-Based Spectroscopy and Microscopy on Nanostructures</h1>.” 2017. Web. 02 Jul 2020.

Vancouver:

Li Z. Absorption-Based Spectroscopy and Microscopy on Nanostructures</h1>. [Internet] [Thesis]. University of Notre Dame; 2017. [cited 2020 Jul 02]. Available from: https://curate.nd.edu/show/2r36tx33r5j.

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

Council of Science Editors:

Li Z. Absorption-Based Spectroscopy and Microscopy on Nanostructures</h1>. [Thesis]. University of Notre Dame; 2017. Available from: https://curate.nd.edu/show/2r36tx33r5j

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

.