We present the results of theoretical studies of the generation process of terahertz radiation arising via interaction of fewcycle
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 mutuallyorthogonal
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.
Numerical solution of the wave equation describing the propagation of laser pulse of a few optical cycles in fused silica is obtained. Our numerical simulations follow closely the published experimental data. We observed a shifting of the spectrum peak of the broadened pulse depending on the input pulse central wavelength.