Physics Commons^™

Study Of Single-Photon Wave-Packets With Atomically Thin Nonlinear Mirrors, Christopher Klenke

Graduate Theses and Dissertations

A novel controlled phase gate for photonic quantum computing is proposed by exploiting the powerful nonlinear optical responses of atomically thin transition metal dichalcogenides (TMDs) and it is shown that such a gate could elicit a π-rad phase shift in the outgoing electric field only in the case of two incident photons and no other cases. Firstly, the motivation for such a gate is developed and then the implementation of monolayer TMDs is presented as a solution to previous realization challenges. The single-mode case of incident photons upon a TMD is derived and is then used to constrain the more …

Fabrication And Characterization Of Photodetector Devices Based On Nanostructured Materials: Graphene And Colloidal Nanocrystals, Wafaa Gebril

Graduate Theses and Dissertations

Photodetectors are devices that capture light signals and convert them into electrical signals. High performance photodetectors are in demand in a variety of applications, such as optical communication, security, and environmental monitoring. Among many appealing nanomaterials for novel photodetection devices, graphene and semiconductor colloidal nanocrystals are promising candidates because of their desirable and unique properties compared to conventional materials.

Photodetector devices based on different types of nanostructured materials including graphene and colloidal nanocrystals were investigated. First, graphene layers were mechanically exfoliated and characterized for device fabrication. Self-powered few layers graphene phototransistors were studied. At zero drain voltage bias and room …

Slow Light With Interleaved P-N Junction To Enhance Performance Of Integrated Mach-Zehnder Silicon Modulators, Marco Passoni, Dario Gerace, Liam O'Faolain, Lucio Claudio Andreani

Cappa Publications

Slow light is a very important concept in nanophotonics, especially in the context of photonic crystals. In this work, we apply our previous design of band-edge slow light in silicon waveguide gratings [M. Passoni et al, Opt. Express 26, 8470 (2018)] to Mach-Zehnder modulators based on the plasma dispersion effect. The key idea is to employ an interleaved p-n junction with the same periodicity as the grating, in order to achieve optimal matching between the electromagnetic field profile and the depletion regions of the p-n junction. The resulting modulation efficiency is strongly improved as compared to common modulators based on …

Compact Optical Frequency Standards For Future Applications Beyond The Laboratory, Kyle Martin

Physics & Astronomy ETDs

Atomic clocks provide one of the fundamental building blocks upon which modern telecommunications systems are constructed. Since the invention of the frequency comb in the early 2000s, laboratory frequency standards have quickly outpaced their compact counterparts. Compact clocks, however, have continued to leverage microwave transitions not yet exploring the advantages of an optical atomic clock. With the recent development of robust frequency combs compact optical clocks can now be realized. In this dissertation two atomic species are investigated for a compact atomic frequency standards. Both of these clocks are in different development stages but offer unique advantages. The optical rubidium …

Semiconductor Color-Center Structure And Excitation Spectra: Equation-Of-Motion Coupled-Cluster Description Of Vacancy And Transition-Metal Defect Photoluminescence, Jesse J. Lutz, Xiaofeng F. Duan, Larry W. Burggraf

Faculty Publications

Valence excitation spectra are computed for deep-center silicon-vacancy defects in 3C, 4H, and 6H silicon carbide (SiC), and comparisons are made with literature photoluminescence measurements. Optimizations of nuclear geometries surrounding the defect centers are performed within a Gaussian basis-set framework using many-body perturbation theory or density functional theory (DFT) methods, with computational expenses minimized by a QM/MM technique called SIMOMM. Vertical excitation energies are subsequently obtained by applying excitation-energy, electron-attached, and ionized equation-of-motion coupled-cluster (EOMCC) methods, where appropriate, as well as time-dependent (TD) DFT, to small models including only a few atoms adjacent to the defect center. We consider the …

Novel Faraday Rotation Effects Observed In Ultra-Thin Iron Garnet Films, Brandon Blasiola

Dissertations, Master's Theses and Master's Reports

Recent work performed by A. Chakravarty and M. Levy showed experimentally a dramatic increase in the specific Faraday Rotation (FR) of the iron garnet Bi_0.8Lu_0.2Gd₂Fe₅O₁₂. A theoretical model, based purely on classical electrodynamics, attempting to explain this behavior was developed by colleagues in Russia that not only confirmed the asymptotic increase in the specific FR at sub-50nm film thicknesses but also suggested that the specific FR should exhibit significant fluctuations at sub-500 nm film thicknesses. The original data points were widespread with steps of 50 nm or more between data …

Weak Values Obtained In Matter-Wave Interferometry, Stephan Sponar, Tobias Denkmayr, Hermann Geppert, Hartmutt Lemmel, Alexandre Matzkin, Jeff Tollaksen, Yuji Hasegawa

Mathematics, Physics, and Computer Science Faculty Articles and Research

Weak values, introduced more than 25 years ago, underwent a metamorphosis from a theoretical curiosity to a powerful resource in photonics for exploring foundations of quantum mechanics, as well as a practical laboratory tool. Due to the tiny coherence volume of particles used in matter-wave optics, a straightforward implementation of weak measurements is not feasible. We have overcome this hurdle by developing a method to weakly measure a massive particle's spin component. A neutron optical approach is realized by utilizing neutron interferometry, where the neutron's spin is coupled weakly to its spatial degree of freedom. Here, we present how one …