Nonreciprocal effects in a ring laser on application of a transverse magnetic field to the active medium

Calculations are made of frequency and amplitude nonreciprocal effects found in a ring laser on application of a transverse magnetic field to the active medium. An analysis is made of the case of quasilinearly polarized opposite waves, which is of interest in practice. It is shown that these effects are due to the nonlinear polarization nonreciprocity found in the active medium on application of a transverse magnetic field. These effects depend on the square of the magnetic field on its orientation with respect to the electric field of the wave. Numerical estimates are made of possible errors in laser gyroscopes caused by transverse magnetic fields. It is suggested that the effects described may be used in laser spectroscopy to determine the relaxation constants of active levels.