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Production, Deceleration, and Detection of OH Radicals

TitleProduction, Deceleration, and Detection of OH Radicals
Publication TypeThesis
Year of Publication2015
AuthorsBriles, TC
Academic DepartmentPhysics
DegreePh.D.
Number of Pages269
Date Published07-2015
UniversityUniversity of Colorado
CityBoulder, CO
Abstract

Samples of cold and ultracold polar molecules have the potential to revolutionize physical chemistry, precision measurement, and few-body quantum physics. This thesis describes experimental results for the production of cold samples of OH radicals by Stark deceleration of a supersonic beam. Since Stark deceleration cannot increase the phase space density of the sample, the initial production stage of the OH molecule is critical. The first set of experiments describes a general methodology for the production of OH beams with maximal phase space density, as well as the subsequent coupling to a Stark decelerator. Additionally, we describe the redesign of our electrostatic trap, optimized for future collision experiments of OH with co-trapped ultracold Rb atoms. The new design resulted in a 15-fold increase in total number of trapped molecules over the previous design when tested with ND3 molecules. The second set of experiments focuses on laser-based detection of OH molecules at the exit of the decelerator based on laser-induced fluorescence (LIF) and resonance-enhanced multiphoton ionizaton (REMPI). The latter method uses vacuum-ultraviolet light at 118 nm produced by third-harmonic generation in Xe/Ar gas mixtures as the ionizing step. The sensitivity of this latter technique is limited by the attainable photon flux of the ionizing radiation at 118 nm. We present detailed measurements of the conversion efficiencies as well as absolute photon fluxes. Strategies to overcome these limitations as well as prospects for detection of OH molecules in a trap are discussed.