Comment: Anomalous Anisotropic Light Scattering in Ge-Doped Silica Glass

This is a comment on a paper by Kazansky et al. appeared in Phys. Rev. Lett., 82, 2199 (1999). We demonstrate that the bremsstrahlung of photoelectrons, which oscillate in the light field of an ultrashort laser pulse, accounts for the anomalous anisotropic light scattering, the "propeller effect", described in the paper of Kazansky et al. This mechanism of light emission could explain some results of white-light continuum generation and dielectric breakdown emission.