Spectral characteristics of a gas saturated by a resonance field

Vladilen S Letokhov

A. P. Kol'Chenko

The nonlinear spectral lineshape of gas absorption near the solid surface in the field of one travelling monochromatic wave is analyzed theoretically. A 'far' zone of distances to the surface, where coherent particle polarization is formed already after their collisions with surface but interparticle collisions in the gas are not yet significant, is considered. It is demonstrated that the narrow saturation sub-Doppler resonances may be appeared on the Doppler lineshape in this zone. These resonances having no analogues in the gas laser spectroscopy. A formation mechanism of such resonances is discussed.

G. K. Ivanov

A. E. Bezrodnyi, Е. А. Титов

А. Ч. Измайлов

A theoretical analysis is made of the resonant interaction between a traveling monochromatic light wave of arbitrary intensity and polarization and the 1/21/2 and 10 transitions in gas atoms in a magnetic field. An analysis is made of the influence of atomic collisions and coherence of the Zeeman sublevels of the terms on the structure of nonlinear magnetooptic resonances in the amplitude and polarization characteristics of the wave. Some features of nonlinear magnetooptic resonances for laser excitation of atoms from the ground state are noted. A study is made of the Faraday rotation and self-rotation of the polarization ellipse of the radiation as a function of the detuning of the wave frequency, the saturation parameter, and the optical density of the gas. The stability of the polarization of light in the medium is discussed. It is noted that these laws may be used to analyze and control the radiation characteristics of lasers and amplifiers when the level of saturation of a resonant gaseous medium in a magnetic field is high.

Alexander M. Starik, O. V. Taranov

An analysis is made of the characteristic features of changes in the refractive index of a molecular gas in the field of resonant radiation when spectral lines overlap. It is shown that, in contrast to absorption in an isolated line, an increase in the gas pressure can alter not only the magnitude but also the sign of the changes in the refractive index.