Atomic, Molecular and Optical Physics Commons^™

Catalysis Of Stark-Tuned Interactions Between Ultracold Rydberg Atoms, A. L. Win, W. D. Williams, T. J. Carroll, C. I. Sukenik

Physics Faculty Publications

We have experimentally investigated a catalysis effect in the resonant energy transfer between ultracold ⁸⁵Rb Rydberg atoms. We studied the time dependence of the process, 34p + 34p → 34s + 35s, and observed an enhancement of 34s state population when 34d state atoms are added. We have also performed numerical model simulations, which are in qualitative agreement with experiment and indicate that the enhancement arises from a redistribution of p-state atoms due to the presence of the d-state atoms.

Imaging The Dipole-Dipole Energy Exchange Between Ultracold Rubidium Rydberg Atoms, Donald P. Fahey, Thomas J. Carroll, Michael W. Noel

Physics and Astronomy Faculty Publications

The long-range, anisotropic nature of the interaction among atoms in an ultracold dipolar gas leads to a rich array of possibilities for studying many-body physics. In this work, an ultracold gas of highly excited atoms is used to study energy transport due to the long-range dipole-dipole interaction. A technique is developed to measure both the internal energy states of the interacting Rydberg atoms and their positions in space. This technique is demonstrated by observing energy exchange between two spatially separated groups of Rydberg atoms excited to two different internal states. Simulations confirm the general features of the energy transport in …

Catalysis Of Stark-Tuned Interactions Between Ultracold Rydberg Atoms, Aye Lu Win

Physics Theses & Dissertations

We present the study of the catalysis effect in the resonant energy transfer between ultracold ⁸⁵Rb Rydberg atoms. We have investigated the energy transfer process of 34p + 34p → 34s + 35s, and observed Stark-tuned Forster resonances. When additional Rydberg atoms of 34d state are included in the interaction, an increase in the population of 34s states atoms is observed. Although the 34d state atoms do not directly participate in the resonant energy transfer that produces 34s state atoms, they add an additional interaction channel 34p + 34 …

A Gauge Theoretic Treatment Of Rovibrational Motion In Diatoms, Gregory Colarch

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Born-Oppenheimer approximation has long been the standard approach to solving the Schrödinger equation for diatomic molecules. In it, nuclear and electronic motions are separated into "slow" and "fast" degrees of freedom and couplings between the two are ignored. The neglect of non-adiabatic couplings leads to an incomplete description of diatomic motion, and in a more refined approach, non-adiabatic couplings are uncoupled by transforming the angular momentum of the molecule and electrons into the body-fixed frame.

In this thesis we examine a "modern" form of the Born-Oppenheimer approximation by exploiting a gauge theoretic approach in a description of molecular motion. …

Spectral Engineering Of Optical Fiber Preforms Through Active Nanoparticle Doping, T. Lindstrom, E. Garber, D. Edmonson, T. Hawkins, Y. Chen, G. Turri, M. Bass, J. Ballato

Publications

Europium doped alkaline earth fluoride [Eu:AEF2 (AE = Ca, Sr, Ba)] nanoparticles were synthesized and systematically incorporated into the core of modified chemical vapor deposition (MCVD)-derived silica-based preforms by solution doping. The resulting preforms were examined to determine the impact of the nanoparticles chemistry on the spectroscopic behavior of the glass. The dominant existence of Eu3+ was demonstrated in all preforms, which is in contrast to conventional solution doped preforms employing dissolved europium salts where Eu2+ is primarily observed. Raman spectroscopy and fluorescence lifetime measurements indicated that the nanoparticles composition is effective in controlling, at a local chemical and structural …

Simulations Of The Dipole-Dipole Interaction Between Two Spatially Separated Groups Of Rydberg Atoms, Thomas J. Carroll, Christopher Daniel, Leah Hoover, Timothy Sidie, Michael W. Noel

Physics and Astronomy Faculty Publications

The dipole-dipole interaction among ultracold Rydberg atoms is simulated. We examine a general interaction scheme in which two atoms excited to the x and x states are converted to y and y states via a Förster resonance. The atoms are arranged in two spatially separated groups, each consisting of only one species of atom. We monitor the state mixing by recording the fraction of atoms excited to the y state as the distance between the two groups is varied. With zero detuning a many-body effect that relies on always resonant interactions causes the state mixing to have a finite range. …

Many-Body Interactions In A Sample Of Ultracold Rydberg Atoms With Varying Dimensions And Densities, Thomas J. Carroll, Shubha Sunder, Michael W. Noel

Physics and Astronomy Faculty Publications

Ultracold highly excited atoms in a magneto-optical trap (MOT) are strongly coupled by the dipole-dipole interaction. We have investigated the importance of many-body effects by controlling the dimensionality and density of the excited sample. We excited three different cylindrical volumes of atoms in the MOT to Rydberg states. At small radius, where the sample is nearly one-dimensional, many-body interactions are suppressed. At larger radii, the sample becomes three-dimensional and many-body effects are apparent.

Angular Dependence Of The Dipole-Dipole Interaction In A Nearly One-Dimensional Sample Of Rydberg Atoms, Thomas J. Carroll, Katharine Claringbould, Anne Goodsell, M. J. Lim, Michael W. Noel

Physics and Astronomy Faculty Publications

Atoms in an ultracold highly excited sample are strongly coupled through the dipole-dipole interaction. In an effort to understand and manipulate the complicated interactions in this system we are investigating their dependence on the relative orientation of the dipoles. By focusing a 480 nm beam from a tunable dye laser into a magneto-optical trap, we produce a nearly one-dimensional sample of Rydberg atoms. The trap lies at the center of four conducting rods with which we can vary the magnitude and direction of the electric field at the trap, thus controlling the orientation of the dipoles with respect to the …

Optical Studies Of Layered Inorganic Solids: A Novel Phase Transition And Energy Transfer Studies., Christie L. Larochelle

Electronic Theses and Dissertations

The optical properties of a group of dicyanoargentates(1) and dicyanoaurates( 1) have been studied. The samples include K2Na[Ag(CN)2I3, Tb[Ag(CN)2]3, Tb[Au(CN)2I3 and a series of compounds of the form Tb,Lal-,[Ag(CN)2]3 with x=0.001, 0.01 and 0.1. Additionally, a novel type of silver-gold mixed- metal sample (L~[A~,Au~-,(CN)~]~ with x=0.9 and 0.5) was synthesized and characterized. The compound K2Na[Ag(CN)2I3 has earlier been shown to exhibit a phenomenon known as luminescence thermochromism, whereby only one emission band is present at very low temperatures and very high temperatures, but a second, lower energy band is also present at intermediate temperatures. This prompted further investigation to explain …

Steady-State Kinetics Of Br(2P1/2) Yields Co2(101) Electronic-To-Vibrational Energy Transfer Laser System, Stephen J. Karis

Theses and Dissertations

Steady state photolysis experiments were conducted to gain information relevant to the construction of a continuous wave electronic to vibrational pumped infrared laser. An Ar⁺ laser =488 µm) was used to produce the electronically excited state Br(²P_1/2) (Br^*) via photolysis of molecular bromine. Energy was then transferred to the near resonant vibrational state CO₂(101) (CO₂) via the collisional quenching of Br^* by CO₂. The dependence of the 2.71 µm Br^* and 4.3 µm CO₂ emissions on CO₂ pressure was measured, as well as …

Infrared Fluorescence Studies Of Electronic-To-Vibrational Energy Transfer In A Br2:No System, Michael R. Hawks

Theses and Dissertations

Steady-state photolysis techniques were used to study electronic-to- vibrational energy transfer mechanisms from atomic bromine to nitric oxide. Molecular bromine was photodissociated by 488nm radiation to produce equal parts Br(²P_1/2) and Br(²P_3/2). Side fluorescence intensity from Br(²P_1/2) at 2.7 µm and from NO (v=1 and 2) around 5.3 µm measured as a function of bromine pressure and nitric oxide pressure. The branching ratio collisional transfer into the first and second states of NO was determined, and previously reported rates for quenching of NO by molecular bromine were verified.

Vibrational Energy Transfer Within The B3Π(0+U) State Of 79Br2 Upon Collision With N2, O2, No, And Sf6, Gregory S. Williams

Theses and Dissertations

Vibrational transfer and electronic quenching in the lower vibrational levels of the ⁷⁹Br₂(B; v'≤3) were investigated using spectrally resolved, temporally resolved pulsed laser induced fluorescence techniques. Spectrally resolved emissions from collisionally populated Br₂(B) vibrational levels were observed for N₂, O₂, NO, and SF₆collision partners. The vibrational transfer was efficient in the nonpredissociative vibrational levels and is adequately described by the Montroll-Shuler model. An average fundamental vibrational transfer rate coefficient of k_v(l,0)=3.4(±0.6) x 10^-11 cm³/molec-sec predicts the vibrational transfer rates for the 0≤v'≤3 collisions with …

Travelling-Wave Sub-Doppler Excited Molecule Energy Transfer Spectroscopy, Khalid Iqbal, Shannon G. Lieb, J. W. Bevan

Scholarship and Professional Work - LAS

A general formulation of traveling‐wave sub‐Doppler excited molecule energy transferspectroscopy is presented. The line profile analysis is applied to that determined experimentally for the R(22) ν3 HCN transition. Pn the noise equivalent power of the detector is demonstrated to be ⩽10−12 W. Finally, the technique is applied to resolve the KsR(7) ν1 transition head in NH3.