Nonlinear self-depolarization effect of high-intensity tightly focused laser beams in transparent isotropic dielectric

摘要

There are presented results of theoretical investigation of nonlinear self-depolarization effect resulting in variation of space distribution of polarization-ellipse parameters of monochromatic high-intensity focused laser beam. Both qualitative consideration of symmetry properties and numerical calculations for Gaussian beams of low order (TE_(00), TE_(01), TE_(10) and TE_(11)) show that linear and circular initial polarizations change and turn into elliptic polarization with inhomogeneous distribution of polarization-ellipse parameters in focal area. Bearing in mind obtained results, we discuss specific symmetry structure of self-depolarization effect allowing experimental checking of described phenomenon. There are analyzed and estimated other contributions to depolarization effect resulting from low-intensity diffraction. Obtained results are generalized for the case of laser pulses and other types of nonlinear optical response of isotropic dielectric.