Theoretical investigation and computational modeling of the difference frequency generation by interaction of few cycle laser pulses in a GaAs crystal

We present the results of theoretical studies of the generation process of difference frequency radiation arising via interaction of mutually orthogonal linearly polarized few-cycle laser pulses propagating in an isotropic nonlinear medium. Numerical time-integration by the finite-difference method of nonlinear Maxwell-equation systems has been performed. We consider the interaction of pulses having the central wavelengths of 1.98 and 1.55 mu m, duration of 30 fs with the corresponding electric field amplitudes of 295 x 106 and 463 x 106 V m-1, propagating along the normal to the < 110 > plane in 854 mu m thickness of GaAs crystal. The process of difference frequency pulse formation arising via spectral filtration of a supercontinuum formed in the spectra of pump pulses at the output of a nonlinear crystal is studied.