Nonlinear dynamics of laser systems at intracavity modulation of polarization

The eigenmode behavior in a resonator and coupled amplitude-polarization dynamics of a HeNe laser operating at λ = 1.15 μm with modulation of anisotropy directions is analyzed analytically and numerically. It is shown that uniform rotation of the directions of the anisotropy results in changes of both the azimuth and ellipticity of the polarization state in the stable lasing regime as well as in periodic dynamics. Modulation by means of nonuniform rotation of the anisotropy induces a parametric resonance phenomenon and quasi-periodic oscillations of the emitted wave parameters. The resonator and laser systems under conditions of parametric resonance can exhibit a sudden change of field polarization parameters because of “quenching” of part of the spectral harmonics appearing as a result of modulation.