Specific features of terahertz radiation emitted from laser sparks induced in gases by femtosecond laser pulses with linear polarization

摘要

The increasing interest to the terahertz radiation is connected with it's unique potential for lots of applications such as identification and detection of different objects and materials for the problems of security, biology, chemistry (see reviews). Some of the most promising alternative for terahertz waves generation are laser plasma methods. Recently in Institute of Applied Physics RAS new experimental data were obtained. In the common scheme of generation (50 fs, 2.5 mJ linear polarized laser pulse, 80–400mm focal length lens) a radiation pattern with strong cylindrical assymetry depending on optic polarization was obtained (see fig. 1 c)[1]. This effect could not be explained in terms of ponderomotive force like in [2] due to it's axisymmetric character.