Physical Sciences and Mathematics Commons^™

Control Of Light-Matter Interactions Via Nanostructured Photonic Materials, Nicholas Proscia

Dissertations, Theses, and Capstone Projects

The thesis here investigates the manipulation of light-matter interactions via nanoscale engineering of material systems. When material systems are structured on the nanoscale, their optical responses can be dramatically altered. In this thesis, this is done in two primary ways: One method is by changing the geometry of nanostructures to induce a resonant behavior with incident electromagnetic field of optical wavelengths. This allows field enhancement in highly localized areas to strengthen exotic light-matter interactions that would otherwise be too weak to measure or for practical use. In this regard, the work presented here studies a voltage produced in a metal …

Control Of Energy Transfer And Molecular Energetics Using Photonic Nanostructures, Rahul Deshmukh

Dissertations, Theses, and Capstone Projects

In the last three decades, the design and fabrication of different types of photonic nanostructures have allowed us to control and enhance the interaction of light (or photons) with matter (or excitons). In this work, we demonstrate the use of three different nanostructures to control different material properties. The design and fabrication of the nanostructures is discussed along with the results obtained using characterization techniques of angle-resolved white light reflectivity and transmission, and time-resolved and steady-state photoluminescence experiments. Specifically, we demonstrate the use of Optical Topological Transitions (OTT) in metamaterials to show enhanced efficiency in the non-radiative transfer of energy …

Using Fundamental Properties Of Light To Investigate Photonic Effects In Condensed Matter And Biological Tissues, Laura A. Sordillo

Dissertations and Theses

Light possesses characteristics such as polarization, wavelength and coherence. The interaction of light and matter, whether in a semiconductor or in a biological sample, can reveal important information about the internal properties of a system. My thesis focuses on two areas: photocarriers in gallium arsenide and biomedical optics. Varying the excitation wavelength can be used to study both biological tissue and condensed matter. I altered the excitation wavelengths to be in the longer near-infrared (NIR) optical windows, in the shortwave infrared (SWIR) range, a wavelength region previously thought to be unusable for medical imaging. With this method, I acquired high …

Impact Of Fiber Parameters On Edfa And/Or Raman Amplified High-Spectral-Efficiency Coherent Wdm Transmissions, Lufeng Leng

Publications and Research

The impact of fiber properties is investigated for coherent systems employing polarization-division multiplexed high-level quadrature amplitude modulation, wavelength-division multiplexing, and erbium-doped fiber amplifier and/or distributed Raman amplification. This is done by comparing the performances of fiber links of various attenuation coefficients and effective areas via experimentally verified analytical methods. Results show that the excess noise, which originates at amplifiers compensating for the losses of filters and switches located between fiber spans, can weaken or even diminish the performance enhancement brought about by lowering the fiber attenuation coefficient, especially if distributed Raman amplification is employed. This leads to the difference in …

Charge State Dynamics And Quantum Sensing With Defects In Diamond, Jacob D. Henshaw

Dissertations, Theses, and Capstone Projects

In recent years, defect centers in wide band gap semiconductors such as diamond, have received significant attention. Defects offer great utility as single photon emitters, nanoscale sensors, and quantum memories and registers for quantum computation. Critical to the utility of these defects, is their charge state.

In this dissertation, experiments surrounding the charge state dynamics and the carrier dynamics are performed and analyzed. Extensive studies of the ionization and recombination processes of defects in diamond, specifically, the Nitrogen Vacancy (NV) center, have been performed. Diffusion of ionized charge carriers has been imaged indirectly through the recapture of said carriers by …

Nanostructured Fibers As A Versatile Photonic Platform: Radiative Cooling And Waveguiding Through Transverse Anderson Localization, Norman Nan Shi, Cheng-Chia Tsai, Michael J. Carter, Jyotirmoy Mandal, Adam C. Overvig, Matthew Y. Sfeir, Ming Lu, Catherine L. Craig, Gary D. Bernard, Yuan Yang, Nanfang Yu

Publications and Research

Broadband high reflectance in nature is often the result of randomly, three-dimensionally structured materials. This study explores unique optical properties associated with one-dimensional nanostructures discovered in silk cocoon fibers of the comet moth, Argema mittrei. The fibers are populated with a high density of air voids randomly distributed across the fiber cross-section but are invariant along the fiber. These filamentary air voids strongly scatter light in the solar spectrum. A single silk fiber measuring ~50 μm thick can reflect 66% of incoming solar radiation, and this, together with the fibers' high emissivity of 0.88 in the mid-infrared range, allows …

Physical Applications Of The Geometric Minimum Action Method, George L. Poppe Jr.

Dissertations, Theses, and Capstone Projects

This thesis extends the landscape of rare events problems solved on stochastic systems by means of the \textit{geometric minimum action method} (gMAM). These include partial differential equations (PDEs) such as the real Ginzburg-Landau equation (RGLE), the linear Schroedinger equation, along with various forms of the nonlinear Schroedinger equation (NLSE) including an application towards an ultra-short pulse mode-locked laser system (MLL).

Additionally we develop analytical tools that can be used alongside numerics to validate those solutions. This includes the use of instanton methods in deriving state transitions for the linear Schroedinger equation and the cubic diffusive NLSE.

These analytical solutions are …

Control Of Light-Matter Interaction In 2d Semiconductors, Zheng Sun

Dissertations, Theses, and Capstone Projects

In this thesis we discuss the control of light matter interaction in low dimensional nanostructure cavity light confining structures. These structures have controllable dispersion properties through design which can be exploited to modify the interaction of light and matter. We will discuss two different types of light confining microcavities: a dielectric cavity and a metal cavity. The specific design of the cavity gives rise to the confinement of the electric field in the center where the nano-materials are placed. In this work, the main material was on the new class of two- dimensional semiconductors of transition metal dichalcogenides (TMDs). Due …

Nonlinear Optical Studies Of Defects And Domain Structures In Perovskite-Type Dielectric Ceramics, David J. Ascienzo

Dissertations, Theses, and Capstone Projects

In order to improve future generations of dielectric capacitors a deeper understanding of voltage-induced dielectric breakdown and electrical energy storage limitations is required. This dissertation presents the use of far-field optical second harmonic generation (SHG) polarimetry for probing structural defects and polar domains in linear and nonlinear perovskite dielectric ceramics. We investigated the formation of electric field-induced structural distortions at pristine Fe-doped SrTiO₃ (Fe:STO) electrode interfaces, structural defect and strain formation due to oxygen vacancy migration in electrodegraded Fe:STO single crystals, and mixed tetragonal and rhombohedral phase domains in ferroelectric Zr-doped BaTiO₃ (BZT) films exhibiting excellent …

Quantum Optical Interferometry And Quantum State Engineering, Richard J. Birrittella Jr

Dissertations, Theses, and Capstone Projects

We highlight some of our research done in the fields of quantum optical interferometry and quantum state engineering. We discuss the body of work for which our research is predicated, as well as discuss some of the fundamental tenants of the theory of phase estimation. We do this in the context of quantum optical interferometry where our primary interest lies in the calculation of the quantum Fisher information as it has been shown that the minimum phase uncertainty obtained, the quantum Cramer-Rao bound, is saturated by parity-based detection methods. We go on to show that the phase uncertainty one obtains …

Wave Propagation Inside Random Media, Xiaojun Cheng

Dissertations, Theses, and Capstone Projects

This thesis presents results of studies of wave scattering within and transmission through random and periodic systems. The main focus is on energy profiles inside quasi-1D and 1D random media.

The connection between transport and the states of the medium is manifested in the equivalence of the dimensionless conductance, g, and the Thouless number which is the ratio of the average linewidth and spacing of energy levels. This equivalence and theories regarding the energy profiles inside random media are based on the assumption that LDOS is uniform throughout the samples. We have conducted microwave measurements of the longitudinal energy profiles …

Optical Forces Generated By Plasmonic Nanostructures, Matthew A. Moocarme

Dissertations, Theses, and Capstone Projects

For millennia, scientists have sought to uncover the secrets of what holds the world together. Optical physicists are often at the forefront, unraveling material properties through investigations of light-matter interactions. As the field has progressed, the smallest unit at which matter can be probed and manipulated has subsequently decreased. The resulting sub-field nanophotonics- which reflects the processing of light at the nanoscale- has blossomed into a vast design space for both applied and theoretical researchers. Plasmonics, the phenomena by which the electron-density of a material oscillates in response to incident electromagnetic radiation, is a subject that has excited nanophotonics researchers …

Photonic Crystals With Alternate Arrays Of Rods And Holes In A Low Dielectric-Index Material, Dimitar L. Dimitrov

Dissertations, Theses, and Capstone Projects

This thesis theoretically deals with the propagation of electromagnetic waves (light beams) in periodically modulated dielectric material structures based on Maxwell’s equations. We are interested in novel light propagation characteristics in these man-made dielectric material structures for practical applications, especially on optical communications and computations. Since the wavelength range of light is on the same order of magnitude as the modulation periods of dielectric materials, an analogy of the light propagation in dielectric-constant modulated structures with the electron transport in solid-state crystals is used throughout my thesis by using a term “photonic crystals (PhCs)” referring to these dielectric structures. I …

Transmission Of Focused Picosecond Light Pulse Through Multimode Fibers, Yin Cen

Dissertations, Theses, and Capstone Projects

This thesis focuses on a technique of delivering spatially focused and temporally compressed picosecond laser pulses through multimode fibers. This study was inspired by recent success in focusing light through optically diffusive media of which multimode fibers were a special case in terms of causing scrambled phase distribution in the transmitted light. The approach involved controlling the phase distribution of incoming beam using a deformable mirror prior to its entry into the multimode fiber in order to achieve constructive interference at selected spots in the output. With phase control, the intensity of the focused light at the output can be …

Control Of Spontanous Emission From Quantum Emitters Using Hyperbolic Metamaterial Substrates, Tal Galfsky

Dissertations, Theses, and Capstone Projects

Hyperbolic metamaterials (HMMs) are so named for possessing a hyperboloid-shaped dispersion which gives rise to a large photonic density of states. Quantum emitters placed inside or in the near-field of a HMM have been shown to exhibit strong enhancement of spontaneous emission due to the increase in available states. This thesis focuses on enhancing spontaneous emission of quantum emitters in optical frequencies by utilizing multilayered metal/dielectric composites that form these highly anisotropic metamaterials. In conjunction with the enhanced decay rate we experimentally demonstrate two methods for shaping and directing radiation trapped in the HMM into free space by employing a …

Experimental Demonstration Of The Microscopic Origin Of Circular Dichroism In Two-Dimensional Metamaterials, Alexander B. Khanikaev, N. Arju, Z. Fan, D. Purtseladze, F. Lu, J. Lee, P. Sarriugarte, M. Schnell, R. Hillenbrand, M. A. Belkin, G. Shvets

Publications and Research

Optical activity and circular dichroism are fascinating physical phenomena originating from the interaction of light with chiral molecules or other nano objects lacking mirror symmetries in three-dimensional (3D) space. While chiral optical properties are weak in most of naturally occurring materials, they can be engineered and significantly enhanced in synthetic optical media known as chiral metamaterials, where the spatial symmetry of their building blocks is broken on a nanoscale. Although originally discovered in 3D structures, circular dichroism can also emerge in a two-dimensional (2D) metasurface. The origin of the resulting circular dichroism is rather subtle, and is related to non-radiative …

Light-Activated Photocurrent Degradation And Self-Healing In Perovskite Solar Cells, Wanyi Nie, Jean-Christophe Blancon, Amanda J. Neukirch, Kannatassen Appavoo, Hsinhan Tsai, Manish Chhowalla, Muhammad A. Alam, Matthew Y. Sfeir, Claudine Katan, Jacky Even, Sergei Tretiak, Jared J. Crochet, Gautam Gupta, Aditya D. Mohite

Publications and Research

Solution-processed organometallic perovskite solar cells have emerged as one of the most promising thin-film photovoltaic technology. However, a key challenge is their lack of stability over prolonged solar irradiation. Few studies have investigated the effect of light soaking on hybrid perovskites and have attributed the degradation in the optoelectronic properties to photochemical or field-assisted ion migration. Here we show that the slow photocurrent degradation in thin-film photovoltaic devices is due to the formation of light-activated meta-stable deep-level trap states. However, the devices can self-heal completely by resting them in the dark for <1 min or the degradation can be completely prevented by operating the devices at 0°C. We investigate several physical mechanisms to explain the microscopic origin for the formation of these trap states, among which the creation of small polaronic states involving localized cooperative lattice strain and molecular orientations emerges as a credible microscopic mechanism requiring further detailed studies.

Properties Of Type-Ii Znte/Znse Submonolayer Quantum Dots Studied Via Excitonic Aharonov-Bohm Effect And Polarized Optical Spectroscopy, Haojie Ji

Dissertations, Theses, and Capstone Projects

In this thesis I develop understanding of the fundamental physical and material properties of type-II ZnTe/ZnSe submonolayer quantum dots (QDs), grown via combination of molecular beam epitaxy (MBE) and migration enhanced epitaxy (MEE). I use magneto-photoluminescence, including excitonic Aharonov-Bohm (AB) effect and polarized optical spectroscopy as the primary tools in this work.

I present previous studies as well as the background of optical and magneto-optical processes in semiconductor nanostructures and introduce the experimental methods in Chapters 1 - 3.

In Chapter 4 I focus on the excitonic AB effect in the type-II QDs. I develop a lateral tightly-bound exciton model …

Ultrafast Spectroscopy And Energy Transfer In An Organic/Inorganic Composite Of Zinc Oxide And Graphite Oxide, Jeff A. Secor

Dissertations, Theses, and Capstone Projects

The energy transfers and nature of defect levels of an organic/inorganic composite of Zinc Oxide and Graphite are studied with multidimensional spectroscopy. The edge and surface states of each composite are uncovered using excitation emission experiments showing which defect states are mediating the energy transfer from the metal oxide to the graphite oxide. Multidimensional time resolved spectroscopy further describes the effect of the carbon phase on the energy transfer pathways in the material.

Zncdmgse As A Materials Platform For Advanced Photonic Devices: Broadband Quantum Cascade Detectors And Green Semiconductor Disk Lasers, Joel De Jesus

Dissertations, Theses, and Capstone Projects

The ZnCdMgSe family of II-VI materials has unique and promising characteristics that may be useful in practical applications. For example they can be grown lattice matched to InP substrates with lattice matched bandgaps that span from 2.1 to 3.5 eV, they can be successfully doped n-type, have a large conduction band offset (CBO) with no intervalley scattering present when strained, they have lower average phonon energies, and the InP lattice constant lies in the middle of the ZnSe and CdSe binaries compounds giving room to experiment with tensile and compressive stress. However they have not been studied in detail for …

Control Of Light-Matter Interaction Via Dispersion Engineering, Harish Natarajan Swaha Krishnamoorthy

Dissertations, Theses, and Capstone Projects

This thesis describes the design, fabrication and characterization of certain nanostructures to engineer light-matter interaction. These materials have peculiar dispersion properties owing to their structural design, which is exploited to control spontaneous emission properties of emitters such as quantum dots and dye molecules. We will discuss two classes of materials based on the size of their unit cell compared to the wavelength of the electromagnetic radiation they interact with. The first class are hyperbolic metamaterials (HMM) composed of alternate layers of a metal and a dielectric of thicknesses much smaller than the wave- length. Using a HMM composed of silver …

Optical Spectroscopy Of Xenon-Related Defects In Diamond, Yury Dziashko

Dissertations, Theses, and Capstone Projects

The work presents the results of optical studies of Xe-related defect in diamond. This defect is one of a few having narrow zero-phonon line in the near-infrared part of the photo-luminescence spectra. It appears in diamond after Xe+ ion implantation followed by thermal annealing. Given unique physical properties of diamond (hardness, optical transparency in wide spectral range, chemical inertness, high thermal conductivity, low thermal expansion coefficient) and stability of Xe-related center it can be viewed as an potential candidate for the source of single-photons, or as optically manipulated qubit, not unlike nitrogen-vacancy center. However, compared to the latter Xe-related center …

Planar Waveguide Structures For Post-Edfa Broadband Near Infrared Optical Amplifiers, Islam Hoxha

Dissertations, Theses, and Capstone Projects

This thesis reports on optical gain of up to 5.7 dB from a planar waveguide with core made of tetravalent chromium-doped calcium germanate single crystal.

Sensitivity Of Orbiting Jem-Euso To Large-Scale Cosmic-Ray Anisotropies, Peter B. Denton, Luis A. Anchordoqui, Andreas A. Berlind, Matthew Richardson, Thomas J. Weiler

Publications and Research

The two main advantages of space-based observation of extreme-energy (& 1019 eV) cosmic-rays (EECRs) over ground-based observatories are the increased field of view, and the all- sky coverage with nearly uniform systematics of an orbiting observatory. The former guarantees increased statistics, whereas the latter enables a partitioning of the sky into spherical harmonics. We have begun an investigation, using the spherical harmonic technique, of the reach of JEM- EUSO into potential anisotropies in the extreme-energy cosmic-ray sky-map. The technique is explained here, and simulations are presented. The discovery of anisotropies would help to identify the long-sought origin of EECRs.

Uv-Visible Microscope Spectrophotometric Polarization And Dichroism With Increased Discrimination Power In Forensic Analysis, Dale Kevin Purcell

All Open Access Legacy Dissertations and Capstone Projects

Microanalysis of transfer (Trace) evidence is the application of a microscope and microscopical techniques for the collection, observation, documentation, examination, identification, and discrimination of micrometer sized particles or domains. Microscope spectrophotometry is the union of microscopy and spectroscopy for microanalysis. Analytical microspectroscopy is the science of studying the emission, reflection, transmission, and absorption of electromagnetic radiation to determine the structure or chemical composition of microscopic-size materials. Microscope spectrophotometry instrument designs have evolved from monochromatic illumination which transmitted through the microscope and sample and then is detected by a photometer detector (photomultiplier tube) to systems in which broad-band (white light) illumination …

Diffuse Optical Imaging Using Decomposition Methods, Binlin Wu, M. Alrubaiee, W. Cai, M. Xu, S. K. Gayen

Publications and Research

Diffuse optical imaging (DOI) for detecting and locating targets in a highly scattering turbid medium is treated as a blind source separation (BSS) problem. Three matrix decomposition methods, independent component analysis (ICA), principal component analysis (PCA), and nonnegative matrix factorization (NMF) were used to study the DOI problem. The efficacy of resulting approaches was evaluated and compared using simulated and experimental data. Samples used in the experiments included Intralipid-10% or Intralipid-20% suspension in water as the medium with absorptive or scattering targets embedded.