"WHITE SUPERCONTINUUM" AND "CONICAL EMISSION" OF FEMTOSECOND FILAMENTS IN BIREFRINGENT MEDIA

The observation of the polarization features of the "white supercontinuum" type and the "conical emission" of femtosecond laser filaments in quartz and sapphire is reported. The features are caused by the positive and negative birefringences of quartz and sapphire. The polarization directions of "white supercontinuum" and "conical emission" are mutually normal as a result of the difference between the group velocities of the ordinary and extraordinary rays. A physical mechanism of conical emission, which explains the features of its polarization, has been proposed.