Date of Award
Master of Science
Department of Engineering Physics
Glen P. Perram, PhD.
To better understand the laser kinetics of an alkali gain medium, hard collisions, or velocity-changing collisions, has been studied and a velocity-changing collisional rate has been calculated. Previous works have studied these collisions, but no rate has been calculated. Using the precise tool of sub-Doppler spectroscopy, atomic hard collisions can be observed. The collected spectra are fitted with two different line shapes to demonstrate the accuracy of this method. From the fits, the number of hard collisions can be extracted. The time scale of the hard collisions in rubidium is interpolated by varying the chopping frequency of the pump beam, or how long the collisions are being observed. Using the time scale and the collisional information from the fits, the velocity-changing collision rate was determined to be 1020.7 ± 26.3s-1mTorr-1 for the first line shape and 758.81 ± 13.90s-1mTorr-1 for the second line shape, which is a 17% and 13% difference, respectively, of the chemical kinetic "hard sphere" collisional model rate, 872.78 ± 13.73s-1mTorr-1.
DTIC Accession Number
Thornton, Douglas E., "Hard Collisions in Rubidium using Sub-Doppler Spectroscopy" (2010). Theses and Dissertations. 2176.