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You searched for +publisher:"University of Louisville" +contributor:("Smadici, Serban"). Showing records 1 – 3 of 3 total matches.

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University of Louisville

1. Hoveyda Marashi, Faren. All-optical switching in ferromagnetic superlattices.

Degree: PhD, 2017, University of Louisville

The unexpected observation of ultrafast demagnetization (UDM) and subsequent time-resolved studies of laser-induced magnetization switching opened a new door to both fundamental physics and technological applications of magnetic materials. All-optical switching (AOS) can be initiated faster than the precession limit, hinting to its potential in increasing the writing speed and data storage density. However, notwithstanding considerable research interest, the mechanism of AOS in ferromagnetic materials remained unclear. Ferromagnetic superlattices were deposited on glass substrates with e-beam evaporation and sputtering. Magnetization curves were measured in magneto-optical and vibrating sample magnetometer experiments. A femtosecond Ti:S laser was utilized in a writing setup to induce AOS in Co/Pd ferromagnetic superlattices at different fluences and beam polarizations. Magnetic force and polarizing microscopy were applied to image the magnetic structure and identify optimal AOS parameters. High-repetition rate pulses of the Ti:S laser resulted in heat accumulation in the samples. For a better understanding of the relation between temperature and domain wall motion, we solved the heat diffusion equation numerically. The solution for our sample displayed a tilted thermal wave front, consistent with the tilted magnetic domains observed. This supports our model of AOS, in which thermal forces acting on domain walls leads to their expansion and magnetization switching (chapter 3). Polarizing microscopy images also revealed a complementary pattern of magnetic domains after laser writing, suggesting that demagnetizing fields are not negligible. Furthermore, comparison of pump-probe UDM measurements with AOS writing measurements pointed to a demagnetized state before AOS emergence. This motivated us to apply micromagnetic simulations to investigate the time evolution of a demagnetized state and in particular the role of demagnetizing fields in the development of different final states. We show using this method that demagnetizing fields can nucleate and, together with thermally-induced forces, develop a switched state (chapter 4). Using the pump-probe setup, we measured the frequency dependence of laser-induced temperature modulations in Co/Au, Co/Ag and Co/Pd superlattices on glass substrates. Green's function solutions of the heat diffusion equation show that a glass layer with properties distinct from the glass substrate is present near the metallic superlattices (chapter 5). Advisors/Committee Members: Smadici, Serban, Jayanthi, Chakram, Jayanthi, Chakram, Sumanasekera, Gamini, Cohn, Robert.

Subjects/Keywords: all-optical switching; magnetization; magneto-optical effects; ultrafast demagnetization; pump-probe experiment; time-resolved study; Condensed Matter Physics

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APA (6th Edition):

Hoveyda Marashi, F. (2017). All-optical switching in ferromagnetic superlattices. (Doctoral Dissertation). University of Louisville. Retrieved from 10.18297/etd/2833 ; https://ir.library.louisville.edu/etd/2833

Chicago Manual of Style (16th Edition):

Hoveyda Marashi, Faren. “All-optical switching in ferromagnetic superlattices.” 2017. Doctoral Dissertation, University of Louisville. Accessed April 12, 2021. 10.18297/etd/2833 ; https://ir.library.louisville.edu/etd/2833.

MLA Handbook (7th Edition):

Hoveyda Marashi, Faren. “All-optical switching in ferromagnetic superlattices.” 2017. Web. 12 Apr 2021.

Vancouver:

Hoveyda Marashi F. All-optical switching in ferromagnetic superlattices. [Internet] [Doctoral dissertation]. University of Louisville; 2017. [cited 2021 Apr 12]. Available from: 10.18297/etd/2833 ; https://ir.library.louisville.edu/etd/2833.

Council of Science Editors:

Hoveyda Marashi F. All-optical switching in ferromagnetic superlattices. [Doctoral Dissertation]. University of Louisville; 2017. Available from: 10.18297/etd/2833 ; https://ir.library.louisville.edu/etd/2833


University of Louisville

2. Ghithan, Jafar Hamed. Photonic tools for advanced sensing and imaging at the nanoscale.

Degree: PhD, 2018, University of Louisville

This dissertation reports a novel bio-sensing strategy based on single-mode, electro-active, integrated optical waveguide (SM-EA-IOW) platforms. It also reports the development of a super-resolved far-field optical imaging tool to enable optical, electronic, and spectroelectrochemical investigations at the nanoscale. SM-EA-IOW platforms with its outstanding sensitivity for spectroelectrochemical interrogation was combined with a sandwich bioassay for the development of a novel immunosensing based strategy for label-free detection of infectious pathogens. The strategy begins with the functionalization of the electroactive waveguide surface with a capturing antibody aimed at a specific target analyte. Once the target analyte is bound to the photonic interface, it promotes the binding of a secondary antibody that has been labeled with a redox active reporter. This labeled antibody reporter forms the analytical signal, which is linked uniquely to both the spectral and electrochemical properties of the redox probe designed to specifically recognize a target analyte. Based on this novel detection strategy experimental results in the interrogation of influenza A (H5N1) HA protein have reached an outstanding level of detection in the picomolar range. In addition, the novel label-free SM-EA-IOW bio-sensing strategy was successfully demonstrated for detection of gram-negative bacteria in present authentic clinical eye samples. Such demonstration has also shown the flexibility and ability of the new strategy to probe samples in in the microliter volume range, without any prior processing or pre-enrichment steps. As the groundwork towards the optimal operation of the novel sensing strategy, the effects of the adsorption process and the rate of electron transfer of redox bound species to the electrode surface were thoroughly studied. For each interface of a multilayer immunoassay assembly the surface density, the adsorption kinetic, and the electron-transfer rate of bound species of a redox-active protein were investigated using an optical impedance spectroscopy (OIS) technique based on measurements obtained with the SM-EA-IOW platform. Such methodology and acquired knowledge are crucial for the rational development of novel and advanced immuno-biosensors. Electrochemically modulated fluorescent molecules to be conjugated with relevant antibodies for creating an electroactive probe at the nanoscale was also investigated. Such capability has the potential to enable the development of an arrayed immunosensing technology. Fluorescence emission at the nanoscale suffers from two main restrictions, diffraction limit and photobleaching effects. To address these hinders, a modulated stimulated emission depletion microscope (STED) that is capable of achieving far-field super-resolved images was developed and used to reduce the power of the applied excitation and depletion laser beams diminish photobleaching effects in single-molecule sub-diffraction STED imaging. These two photonic devices provide new approaches for bio-sensing from… Advisors/Committee Members: Mendes, Sergio B., O'Toole, Martin G., O'Toole, Martin G., Smadici, Serban, Yu, Ming, Yappert, Cecilia.

Subjects/Keywords: waveguide; spectroelectrochemistry; STED; electroactive; biosensors; Biological and Chemical Physics; Biophysics; Optics

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

APA (6th Edition):

Ghithan, J. H. (2018). Photonic tools for advanced sensing and imaging at the nanoscale. (Doctoral Dissertation). University of Louisville. Retrieved from 10.18297/etd/2933 ; https://ir.library.louisville.edu/etd/2933

Chicago Manual of Style (16th Edition):

Ghithan, Jafar Hamed. “Photonic tools for advanced sensing and imaging at the nanoscale.” 2018. Doctoral Dissertation, University of Louisville. Accessed April 12, 2021. 10.18297/etd/2933 ; https://ir.library.louisville.edu/etd/2933.

MLA Handbook (7th Edition):

Ghithan, Jafar Hamed. “Photonic tools for advanced sensing and imaging at the nanoscale.” 2018. Web. 12 Apr 2021.

Vancouver:

Ghithan JH. Photonic tools for advanced sensing and imaging at the nanoscale. [Internet] [Doctoral dissertation]. University of Louisville; 2018. [cited 2021 Apr 12]. Available from: 10.18297/etd/2933 ; https://ir.library.louisville.edu/etd/2933.

Council of Science Editors:

Ghithan JH. Photonic tools for advanced sensing and imaging at the nanoscale. [Doctoral Dissertation]. University of Louisville; 2018. Available from: 10.18297/etd/2933 ; https://ir.library.louisville.edu/etd/2933

3. Colston, Jacob. A study of the radiative pion capture process as a background to the search for muon to electron conversion with the mu2e experiment.

Degree: MS, 2016, University of Louisville

This thesis will introduce radiative pion capture (RPC), a process which can produce a fake signal in a search for the coherent conversion of a muon to an electron in the presence of a nucleus. There will be a brief introduction to standard model (SM) physics, as well as some more in-depth discussion of the relevant high energy physics at the Mu2e experiment. We will discuss charged lepton flavor violation (CLFV), as well as Supersymmetry, which predicts CLFV at higher intensities than the SM prediction. A description of the RPC process follows, including the external and internal conversions in pion captures, and these processes' contributions to background at Mu2e. We will conclude with an estimate of the background contributions as obtained with analysis of Monte Carlo simulations. Advisors/Committee Members: Brown, David, Davis, Christopher, Davis, Christopher, Wildstrom, Jacob, Smadici, Serban.

Subjects/Keywords: particle physics; experimental particle physics; high energy physics; experimental high energy physics; backgrounds; Mu2e; Elementary Particles and Fields and String Theory

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

APA (6th Edition):

Colston, J. (2016). A study of the radiative pion capture process as a background to the search for muon to electron conversion with the mu2e experiment. (Masters Thesis). University of Louisville. Retrieved from 10.18297/etd/2509 ; https://ir.library.louisville.edu/etd/2509

Chicago Manual of Style (16th Edition):

Colston, Jacob. “A study of the radiative pion capture process as a background to the search for muon to electron conversion with the mu2e experiment.” 2016. Masters Thesis, University of Louisville. Accessed April 12, 2021. 10.18297/etd/2509 ; https://ir.library.louisville.edu/etd/2509.

MLA Handbook (7th Edition):

Colston, Jacob. “A study of the radiative pion capture process as a background to the search for muon to electron conversion with the mu2e experiment.” 2016. Web. 12 Apr 2021.

Vancouver:

Colston J. A study of the radiative pion capture process as a background to the search for muon to electron conversion with the mu2e experiment. [Internet] [Masters thesis]. University of Louisville; 2016. [cited 2021 Apr 12]. Available from: 10.18297/etd/2509 ; https://ir.library.louisville.edu/etd/2509.

Council of Science Editors:

Colston J. A study of the radiative pion capture process as a background to the search for muon to electron conversion with the mu2e experiment. [Masters Thesis]. University of Louisville; 2016. Available from: 10.18297/etd/2509 ; https://ir.library.louisville.edu/etd/2509

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