Helium 2(3)S(1) optical pumping with lasers
Soletsky, Philip A.
Dunning, F. B.
Master of Science
Continued improvement of a single-mode frequency-stabilized 1.083 $\mu$m LNA laser developed at this laboratory has resulted in greater frequency stability and higher output power. Use of this laser with the Rice Flowing Helium Afterglow apparatus has resulted in considerable insight into Penning ionization reaction processes. Also, in the present work, a modified Coherent Inc. CR899-21 Ti:Sapphire laser is being used as a source of 1.083 $\mu$m radiation. A simple technique using a confocal Fabry-Perot etalon and stabilized helium-neon laser is used to limit long-term drift in the laser output frequency to $\leq$1 MHz per day. Measurements using a beam of He(2$\sp3$S) atoms show that the laser can provide stable He(2$\sp3$S) optical pumping resulting in polarizations approaching 100%. The laser is also being employed in studies of He(2$\sp3$P) collisions at low temperatures using laser-induced fluorescence and line-shape analysis. (Abstract shortened with permission of author.)
Atomic physics; Optics