TERAHERTZ FIELD EXCITATION FROM A PLASMA SLAB WITH LASER PULSE INTERACTION

Abstract

We consider the excitation of terahertz (THz) radiation using the interaction of a Gaussian laser pulse with a plasma slab. Using the properties of the Gaussian laser pulse, the terahertz radiation is produced in the plasma slab. It is found that the ponderomotive force produced by the laser causes oscillations of the plasma electrons' velocity, and the ponderomotive potential of the laser generates the terahertz radiation in the plasma slab. The dependency of the field excited on the axial and radial dimensions of the plasma slab, as well as the duration and spot size of the laser pulse, is considered. We have found that the amplitude of the excited field increases four times for a highly focused laser pulse. It is found that the excitation of the terahertz radial fields is most effective in the case of the generation frequency close to the plasma frequency and when the duration of the laser pulse is about the same as the axial dimension of the plasma slab.