Spontaneous Radiation by Atoms in Lasers

Marvin H. Mittleman

A. D. Gazazyan, Y. Pashayan-Leroy

Marvin H. Mittleman

In the first paper of this series a formal theory of atomic scattering of electrons in the presence of an intense electromagnetic field was given. Cross sections, near the forward direction, between atomic states (modified by the laser) were obtained. However, it was assumed that the atom could not emit spontaneous radiation. In this paper the effect of spontaneous radiation is included, and it is shown that in most cases the measured cross section will be a weighted average of the two different cross sections starting from the two different initial states which are those atomic states resonantly linked by the laser. The Born approximation for the scattering is obtained, and it is shown that for the simplest description of the spontaneous radiation field the effect of the laser on the cross sections is simply to multiply them by a factor which depends upon the laser detuning.

Sergei G Rautian, Anatolii M. Shalagin

A theoretical analysis is made of the polarization of atomic states (inhomogeneous distribution over magnetic sublevels) induced by collisions with particles polarized by a laser field. The transfer of polarization may be observed by investigating the polarization of the spontaneous radiation emitted from atoms. The polarization tensor of such spontaneous radiation is calculated. A close relationship between the components of this tensor and the characteristics of an elementary scattering event is established.

Franz Schwabl, Walter E Thirring

Vladimir P Bykov, G V Shepelev

Spontaneous and stimulated emission from atoms in a free one-dimensional space is considered from the quantum-mechanical point of view. The resolvent method is used to calculate the field density matrix, average electric field, and electromagnetic field energy density for a spontaneously emitting atom. For an atom emitting in the field of another atom, calculations are made of the electric field of the spontaneous and stimulated radiation. It is shown how the coherence length and coherence time of the spontaneous radiation increase. The application of these results in laser theory to explain the formation of a radiation mode structure and consequent appearance of coherent radiation is discussed.