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Full-Text Articles in Physics

Electroluminescence Studies On Longwavelength Indium Arsenide Quantum Dot Microcavities Grown On Gallium Arsenide, John C. Ramsey Dec 2011

Electroluminescence Studies On Longwavelength Indium Arsenide Quantum Dot Microcavities Grown On Gallium Arsenide, John C. Ramsey

Theses and Dissertations

A comprehensive study of the electroluminescence of four GaAs/AlGaAs microcavity devices with InAs/GaInAs quantum dot active regions emitting near 1.3 µm was conducted. The four molecular beam epitaxial grown samples with AlAs oxide aperture confinement layers were fabricated, characterized, and optically modeled. Optical power transmission of the samples was modeled using Matlab and compared with measured transmission data. Resonant cavity light emitting diodes (RCLEDs) and three vertical cavity surface emitting laser (VCSEL) samples were fabricated and electro-optically characterized over a range of injection currents and temperatures. Devices achieved continuous wave room temperature lasing at 1.28 µm with an output power …


Generation Of Isolated Attosecond Extreme Ultraviolet Pulses: Optimization Of Coupled Ellipsoids, Sarah L. Stebbings, F. Süßmann, Y-Y Yang, A. Scrinzi, Maxim Durach, Anastasia Rusina, Mark I. Stockman, Matthias F. Kling Jan 2011

Generation Of Isolated Attosecond Extreme Ultraviolet Pulses: Optimization Of Coupled Ellipsoids, Sarah L. Stebbings, F. Süßmann, Y-Y Yang, A. Scrinzi, Maxim Durach, Anastasia Rusina, Mark I. Stockman, Matthias F. Kling

Maxim Durach

The production of extreme ultraviolet (XUV) radiation via nanoplasmonic field-enhanced high-harmonic generation (HHG) in gold nanostructures at MHz repetition rates is investigated theoretically in this paper. Analytical and numerical calculations are employed and compared in order to determine the plasmonic fields in gold ellipsoidal nanoparticles. The comparison indicates that numerical calculations can accurately predict the field enhancement and plasmonic decay, but may encounter difficulties when attempting to predict the oscillatory behavior of the plasmonic field. Numerical calculations for coupled symmetric and asymmetric ellipsoids for different carrier-envelope phases (CEPs) of the driving laser field are combined with time-dependent Schrödinger equation simulations …


Computational Study Of The Near Field Spontaneous Creation Of Photonic States Coupled To Few Level Systems, Sergio Tafur Jan 2011

Computational Study Of The Near Field Spontaneous Creation Of Photonic States Coupled To Few Level Systems, Sergio Tafur

Electronic Theses and Dissertations

Models of the spontaneous emission and absorption of photons coupled to the electronic states of quantum dots, molecules, N-V (single nitrogen vacancy) centers in diamond, that can be modeled as artificial few level atoms, are important to the development of quantum computers and quantum networks. A quantum source modeled after an effective few level system is strongly dependent on the type and coupling strength the allowed transitions. These selection rules are subject to the Wigner-Eckert theorem which specifies the possible transitions during the spontaneous creation of a photonic state and its subsequent emission. The model presented in this dissertation describes …


Tunneling Conductance Characterization Of A Quantum Dot In The Fractional Quantum Hall Regime, Douglas E. Willard Jan 2011

Tunneling Conductance Characterization Of A Quantum Dot In The Fractional Quantum Hall Regime, Douglas E. Willard

Electronic Theses and Dissertations

This work represents a first-principles calculation of the electron tunneling current into quantum dots in the fractional quantum Hall effect regime. The system under consideration consists of an idealized Scanning Tunneling Microscope (STM) tip and a quantum dot with disk geometry and interacting electrons in a transverse magnetic field. Within the context of this model the tunneling current between the STM tip and the dot is examined for spin-polarized electrons at and around a filling factor of 1/3. The current expression is based on a second-quantized Hamiltonian in which electrons in the dot are interacting, confined, and restricted to the …


Optically Injected And Mutually Coupled Frequency Distinct Semiconductor Lasers, Beatriz Baselga-Pascual Jan 2011

Optically Injected And Mutually Coupled Frequency Distinct Semiconductor Lasers, Beatriz Baselga-Pascual

Theses

In the following work we examine the dynamics of semiconductor lasers under different types of coupled oscillator configurations, namely optical injection and mutual coupling. We examine both discrete-mode quantum well lasers and distribute feedback quantum dot lasers. First we describe optical injection experiments carried out on single mode semiconductor lasers. Conventional diagnostic tools such as optical spectra, RF spectra and intensity time series are used to describe the dynamics. We also describe a novel interferometric technique used to experimentally resolve the phase of the slave laser. This new technique has proved successful, revealing some heretofore hidden dynamical features and showing …