Modeling of difference frequency radiation energy redistribution process in a spectrum of laser pulse of a few optical cycles propagating in a quasi-phase-matching GaAs crystal

Abstract

We present the results of a numerical study of the generation process of difference frequency radiation (DFR) arising via the interaction of mutually orthogonal linearly- polarized few-cycle laser pulses propagating in a quasi-phase-matching (QPM) GaAs crystal. Considered the interaction of pulses having the central wavelengths of 1.98 µm, duration of 30 fs with the electric field amplitude 200 MV/m, propagating along the normal to the ⟨110⟩ plane. The period Λ of the QPM GaAs crystal in numerical simulations varied from 20.89 µm to 53.23 µm. It is shown that by changing the grating period of the QPM GaAs crystal from 23.02 µm to 37.29 µm it is possible to improve the efficiency of QPM generation of DFR in the 5.48 µm – 10.12 µm spectral range at least by 8 dB in comparison with the generation of DFR in bulk crystal GaAs in the same spectral range.