Generation of terahertz radiation under the effect of a femtosecond pulse on plasma in a magnetic field.

Abstract

The generation of terahertz (THz) radiation under the effect of a femtosecond laser pulse on a transparent semibounded plasma in a constant magnetic field is studied. It is shown how the generation patterns of THz radiation depend on the laser pulse duration and the ratio between the cyclotron and plasma frequencies of electrons. In each of the modes considered, the total energy per unit area, spectral composition, and pulse shape of the generated THz radiation are found. It has been established that optimal generation conditions are realized at laser pulse duration comparable to the reciprocal frequency of plasma oscillations and at electron cyclotron frequency lower than plasma frequency. When cyclotron frequency exceeds plasma frequency, the possibility of increasing the generation frequency up to frequencies comparable to the cyclotron frequency is revealed.