Atomic, Molecular and Optical Physics Commons^™

Testing Quantum Randomness In Single-Photon Polarization Measurements With The Nist Test Suite, David Branning, Matthew Bermudez

Faculty Scholarship

A binary sequence was constructed from 1.7×10⁷ polarization measurements of single photons from a spontaneous parametric downconversion source, under pumping conditions similar to those used in optical quantum cryptography. To search for correlations in the polarization measurement outcomes, we subjected the sequence to a suite of tests developed at the National Institute of Standards and Technology (NIST) for the assessment of algorithmic random-number generators. The bias of the sequence was low enough to allow all fifteen tests to be applied directly to the polarization outcomes without using any numerical unbiasing procedures. No statistically significant deviations from randomness were observed, …

Time-Resolved Compton Scattering For A Model Fermion-Boson System, R E. Wagner, Rainer Grobe, Q Su

Faculty publications – Physics

We study the scattering of a boson with a fermion with full spatial and temporal resolution based on the one-dimensional Yukawa Hamiltonian. In quantum field theory this interaction is described by the annihilation and creation of bosons with intermediate virtual particle states. We show that this process can be modeled in the center-of-mass frame by a scattering potential, permitting us to interpret the absorption and re-emission processes in quantum mechanical terms of a characteristic force. This Compton force between the fermion and boson is repulsive for large distances and attractive for shorter spacings. We also examine the periodic dynamics of …

Vibrational Spectroscopic Study Of The 1,3,5,7-Cyclooctatetraene At High Static Pressures, Edward Romano

UNLV Theses, Dissertations, Professional Papers, and Capstones

1,3,5,7-cyclooctatetraene (COT) is a single-ringed hydrocarbon that has not been studied extensively under high static pressures. It was the intent of this study to reveal its high-pressure behavior through its vibrational spectra. To this end, its infrared spectra as a function of pressure were collected at the National Synchrotron Light Source (NSLS) U2A beamline, as well as its Raman spectra over pressure using a micro-Raman spectrometer.

The spectra show the typical stiffening of force constants with increasing pressure for most peaks, particularly those which would theoretically exhibit a mode-softening behavior under hypotheses of molecular planarization and aromatization. Additionally, the data …

Effect Of Particle Properties And Light Polarization On The Plasmonic Resonances In Metallic Nanoparticles, U. Guler, R. Turan

U. Guler

The resonance behavior of localized surface plasmons in silver and gold nanoparticles was studied in the visible and near-infrared regions of the electromagnetic spectrum. Arrays of nano-sized gold (Au) and silver (Ag) particles with different properties were produced with electron-beam lithography technique over glass substrates. The effect of the particle size, shape variations, period, thickness, metal type, substrate type and sulfidation were studied via transmission and reflectance measurements. The results are compared with the theoretical calculations based on the DDA simulations performed by software developed in this study. We propose a new intensity modulation technique based on localized surface plasmons …

Experimental And Theoretical Studies On Nitrogen Plasma And Methane Photolysis: Implications For Laboratory Simulations Of Titan’S Atmosphere, M-C. Gazeau, Y. Benilan, E. Arzoumanian, Et. Es-Sebbar, A. Jolly

Dr. Et-touhami Es-sebbar

No abstract provided.

Spectroscopic Studies Applied To Uvis Observations Of Titan, Y. Benilan, F. Capalbo, Et. Es-Sebbar, N. Fray, A. Jolly, M-C. Gazeau, J-C. Guillemin, M. Schwell

Dr. Et-touhami Es-sebbar

No abstract provided.

Talif Investigation And Modelling Of The Absolute N(4s) Density In A N2-Ch4 Late Afterglow, C.D. Pintassilgo, Et. Es-Sebbar, Y. Benilan, M-C. Gazeau, A. Jolly

Dr. Et-touhami Es-sebbar

The purpose of the present work is the experimental and numerical study of the absolute ground-state nitrogen atoms density N(4S) in the late afterglow of a pure N2 flowing microwave discharge in which different amounts of CH4 have been injected at 25 cm downstream from the nitrogen discharge. The absolute N(4S) concentrations have been measured using Two-photon Absorption Laser-Induced Fluorescence (TALIF), while a detailed kinetic model has been developed to simulate both the discharge and the post-discharge regions. Theoretical predictions are then compared to experimental measurements.

Combined Experimental And Theoretical Studies On Methane Photolysis At 121.6 Nm And 248 Nm- Implications On A Program Of Laboratory Simulations Of Titan’S Atmosphere, C. Romanzin, E. Arzoumanian, Et. Es-Sebbar, A. Jolly, S. Perrier, M.-C. Gazeau, Y. Bénilan

Dr. Et-touhami Es-sebbar

Methane is, together with N2, the main precursor of Titan’s atmospheric chemistry. In our laboratory, we are currently developing a program of laboratory simulations of Titan’s atmosphere, where methane is intended to be dissociated by multiphotonic photolysis at 248 nm. A preliminary study has shown that multiphotonic absorption of methane at 248 nm is efficient and leads to the production of hydrocarbons such as C2H2 (Romanzin et al., 2008). Yet, at this wavelength, little is known about the branching ratios of the hydrocarbon radicals (CH3, CH2 and CH) and their following photochemistry. This paper thus aims at investigating methane photochemistry …

Spectroscopic Study Of Ultracold Rubidium Atoms In An Optical Dipole Force Trap, Eman Mohammed Ahmed

Physics Theses & Dissertations

The interaction of light with atoms and molecules is of fundamental interest in many branches of science. In atomic physics, this interaction can be used to cool and spatially confine (trap) atoms. These traps can be used as the starting point for other experiments, but the dynamics of the cooling and trapping processes is itself of interest. In order to better understand the physics of trapping atoms in an optical dipole force trap, we have conducted a series of spectroscopic measurements of ultracold rubidium atoms in such a trap. The trap was created at the focus of a Nd:YAG laser …

Communications: Chain And Double-Ring Polymeric Structures: Observation Of Alnh3n+1 − (N=4–8) And Al4h14 −, Xiang Li, Andrej Grubisic, Kit H. Bowen, Anil K. Kandalam, Boggavarapu Kiran, Gerd F. Gantefoer, Puru Jena

Physics & Engineering Faculty Publications

No abstract provided.

Temperature-Dependent Photoabsorption Cross-Section Of Cyano-Diacetylene In The Vacuum Uv, N. Fray, Y. Bénilan, M.-C. Gazeau, A. Jolly, M. Schwell, E. Arzoumanian, Et. Es-Sebbar, T. Ferradaz, J.- C. Guillemin

Dr. Et-touhami Es-sebbar

Using synchrotron radiation as a tunable VUV light source, we have measured, for the first time, the absolute photoabsorption cross sections of HC5N with a spectral resolution of 0.05 nm in the region between 80 and 205 nm from 233 to 298 K. The measured cross sections are used to predict the HC5N photodestruction rate in the solar system and to model a transmission spectrum in Titan's atmosphere. Comparing the latter with that acquired by the Ultraviolet Imaging Spectrograph on board the Cassini spacecraft, we have determined an upper limit of 2.7 × 10−5 on the HC5N abundance at 1100 …

Design And Construction Of A Thermal Diffusion Cloud Chamber, Alexander Donoghue

Physics

This paper will cover the theory behind a thermal diffusion cloud chamber. In addition to that it will cover the process, thought and material used to construct two different cloud chambers. It will also discuss the effects of materials used in each chamber on the working of the chamber.

Optical Coherence: Recreation Of The Experiment Of Thompson And Wolf, David Collins

Physics

The purpose of our experiment is to recreate the experiment done by Thompson and Wolf in 1957 on the measurement of optical coherence. What is novel about our approach is that it allows one to view the effects of source size on optical spatial coherence in real time.

Collisional Transfer Of Population And Orientation In Nak, Seth T. Ashman, C. M. Wolfe, J. Huennekens, B. Beser, J. Bai, A. M. Lyyra

Engineering & Physics Faculty Publications

We report current work to study transfer of population and orientation in collisions of NaK molecules with argon and potassium atoms using polarization labeling (PL) and laser- induced fluorescence (LIF) spectroscopy. In the PL experiment, a circularly polarized pump laser excites a specific NaK A1Σ +(v 0=16, J 0 ) ← X1Σ +(v 00=0, J 0 ± 1) transition, creating an orientation (non-uniform MJ0 level distribution) in both levels. The linearly polarized probe laser is scanned over various 31Π(v, J 0±1) ← A1Σ +(v 0=16, J 0 ) transitions. The probe laser passes through a crossed linear polarizer before detection, …

Experimental Studies Of The Nacs 53Π0 And 1(A)3Σ+ States, Seth T. Ashman, Brett Mcgeehan, Christopher Wolfe, Carl Faust, John Huennekens

Engineering & Physics Faculty Publications

We present experimental studies of the NaCs molecule that are currently underway in our laboratory. The opticaloptical double resonance method is used to obtain Doppler-free excitation spectra for several excited states. Selected data from the 53Π0 electronic state are used to obtain Rydberg-Klein-Rees (RKR) and Inverse Perturbation Approach (IPA) potential curves. We are also mapping the repulsive wall of the 1(a) 3Σ +potential using many resolved bound-free fluorescence spectra from individual ro-vibrational levels of the 53Π0 electronic state to the 1(a) 3Σ + state. Using the determined 53Π0 state potential we fit the repulsive wall of the 1(a) 3Σ + …

Exponential Enhancement Of Field-Induced Pair Creation From The Bosonic Vacuum, R E. Wagner, M R. Ware, Q Su, Rainer Grobe

Faculty publications – Physics

Using numerical solutions to quantum field theory, the creation of boson-antiboson pairs from the vacuum under a very strong localized external electric field is explored. The simulations reveal that the initial linear increase of the number of particles turns into an exponential growth. This self-amplification can be understood as the result of the interaction of the previously generated particles with the creation process. While the number of particles keeps increasing, the spatial shape of the (normalized) charge density of the created particles reaches a universal form that can be related to the bound states of the supercritical potential well. We …

Design Of Electronics For A High-Energy Photon Tagger For The Gluex Experiment, Mitchell "Woody" Underwood

Honors Scholar Theses

In quantum chromodynamics (QCD), quarks and antiquarks are held together inside hadrons by the nuclear strong force, which is mediated by exchange particles known as gluons. The simplest type of hadron, the meson, consists of a single quark and a single antiquark bound by a gluonic field. The flux-tube model of QCD says that this gluonic field forms a tube of color-electric field lines between the quark and the antiquark which can under the right conditions be made to vibrate. Such mesons with excited glue are called hybrid mesons.

GlueX is a high-energy nuclear physics experiment which will study hybrid …

Partial Phonon Density Of States Of 57-Iron And 161-Dysprosium In Dyfe3 By Nuclear Resonant Inelastic X-Ray Scattering Under High Pressure, Elizabeth Anne Tanis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The dual partial phonon density of states (DOS) from two different Mossbauer isotopes (161Dy and 57Fe) in the same material (DyFe3) was successfully measured using the nuclear resonant inelastic x-ray scattering (NRIXS) technique at high pressure. Nuclear inelastic scattering measurements yield an in-depth understanding of the element-specific dynamic properties. The Debye temperatures , the Lamb-Mossbauer factor, and the vibrational contributions to the Helmholtz free energy, specific heat , entropy and internal energy are calculated directly from the phonon density of states.

Optical Properties Of Type Iii-V Semiconductor Spherical Quantum Dot Heterostructures, Nathan Haluska

Master's Theses - Daytona Beach

In recent years quantum dots (QD) have attracted increasing interest because of their wide variety of revolutionary applications. Such applications include high speed optical communication lasers, infrared photodetectors, and single photon emitters. One promising immediate application is QD solar cells. Proper analysis of the optical absorption characteristics in these solar cells requires a rigorous modeling of the electronic structure and optical properties of semiconductor heterostructures. Our emphasis will be on type III-V semiconductors. Such structures, have a great potential for increasing efficiencies, but they also possess highly degenerate and complex valence band structures. Therefore, we seek to develop a model …

Measurement Of Γ-Emission Branching Ratios For 154,156,158Gd Compound Nuclei: Tests Of Surrogate Nuclear Reaction Approximations For (N,Γ) Cross Sections, N. D. Scielzo

Physics Faculty Publications

The surrogate nuclear reaction method can be used to determine neutron-induced reaction cross sections from measured decay properties of a compound nucleus created using a different reaction and calculated formation cross sections. The reliability of (n,γ) cross sections determined using the Weisskopf-Ewing and ratio approximations are explored for the ^{155, 157}Gd(n,γ) reactions. Enriched gadolinium targets were bombarded with 22-MeV protons and γ rays were detected in coincidence with scattered protons using the Silicon Telescope Array for Reaction Studies/Livermore-Berkeley Array for Collaborative Experiments (STARS/LiBerACE) silicon and germanium detector arrays. The γ-emission probabilities for the ^{154, 156, …}