Strong field effects in spectroscopy of degenerated metastable atoms

In the introduced paper the results of theoretical and experimental investigations in a branch of probe-field spectroscopy of degenerated metastable atoms in a laser radiation field of arbitrary intensity with taking into account of its anisotropical excitation and the presence of additional channels of radiant decay of upper level are presented. It is shown that for the degenerated levels which are excited anisotropically the absorption spectrum of the probe field contains, besides resonances caused by occupancy effects, resonances associated with the magnetic coherence and manifested in the form of peaks and dips with substantially different amplitudes and widths. A fundamentally new property of these resonances is that their widths are proportional to the intensity of the orienting field, and the amplitude of the narrowest resonance becomes appreciable when the orienting field is very strong.