LASER GENERATION WITHOUT POPULATION INVERSION IN THE В«RED» WING OF THE D1 LINE OF ALKALI METAL ATOMS UNDER RESONANT DIODE PUMPING
A. I. Parkhomenko, A. M. Shalagin
Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: alkali metal atoms, inversionless amplification of radiation, diode pumping, collisions, Einstein coefficients, spectral line wing
Abstract
A new method for generating laser radiation without population inversion in the «red» wing of the D1 line of alkali metal atoms under resonant absorption of broadband radiation from pump laser diodes at the D1 transition has been theoretically investigated. The reason for the occurrence of laser generation is the fact that the probability of stimulated emission in the red wing of the spectral line exceeds the probability of absorption if the uniform broadening due to the interaction of active particles with the buffer gas significantly exceeds the natural one (at high pressures of the buffer gas). Analytical formulas that describe the operation of an alkali metal vapor laser under transverse diode pumping are derived. It has been found that the most promising objects for observing laser lasing without population inversion in the red wing of the D1 line of alkali metal atoms are cesium atoms. In a sufficiently long active medium (the length of the medium is 50 times greater than its width), the conversion efficiency of pump radiation into laser radiation can reach 57% at a buffer gas pressure of 5 atm, a pump diode radiation intensity of 5 kW/cm2, and a half-width of its spectrum of 1 cm-1. The frequency of laser radiation can be tuned by several tens of cm-1.
|
