Discharge-pumped cw gas lasers utilizing "dressed-atom" gain media

Abstract

The possibility of realizing an efficient gaseous laser-beam-generating medium that utilizes Λ-type coherently phased (i.e., "dressed") atoms for the active laser species, but that does not inherently require the use of external laser beams for pumping, is explored. Specifically, it is investigated if multiphoton stimulated hyper-Raman scattering (SHRS) processes driven by fluorescence radiation generated in a continuous electrical discharge present within the vapor-containing cell could produce continuous-wave (cw) optical gain at the Λ-atom resonance frequencies ωo and ωo′. It is deduced that such gain could result from n-photon (n≥4) SHRS processes only if absorption of fluorescence pump light occurs in the first three transitions of the n-photon sequence representing the process unit step. Estimates of the amount of optical gain that could be produced in such a system indicate that it should be sufficient to allow multiwatt cw laser operation to occur on one set of Λ transitions connecting levels in a "double-Λ" structure, with the pump light being discharge-produced fluorescence centered about the transitions of the other Λ pair. However, to initiate operation of such a device would require injection into the laser optical cavity of intense "starter" laser pulses at both lasing frequencies. What should be an optimal experimental configuration for determining feasibility of the proposed laser device is described. In the suggested configuration, Cs-atom 6S1.2-6P1.2 transitions form the double-Λ structure. © 2005 The American Physical Society.