Terahertz Pulse Generation by the Method of Optical Rectification ofFew-Cycle Laser Pulses Propagating in GaAs Crystal

摘要

We present the results of theoretical studies of the generation process of terahertz radiation arising via interaction of few-cycle laser pulses propagating in an isotropic nonlinear medium. Numerical time-integration by the finite-difference method of the system of nonlinear Maxwell equations has been performed. We consider the interaction of mutually-orthogonal linearly polarized pulses, both having the central wavelength of 1.98 μm, duration of 30 fs and the energies of 30 nJ, propagating along the normal to the <110> plane in the 1 mm-thickness GaAs crystal. The process of formation of a terahertz pulse arising via spectral filtration of supercontinuum formed in the spectra of pump pulses at the output of nonlinear crystal is studied. The dependences of both current frequency of the pump pulses on time for different lengths of nonlinear crystal and of pump pulse durations on the crystal length are obtained.