Summary and difference frequency radiation generation in the field of few-cycle laser pulse propagating in GaSe

Abstract

The results of numerical study of the generation process of summary and difference frequency radiations (SFR and DFR) arising via interaction of linearly polarized a few cycle laser pulses propagating in a GaSe crystal is present. The interaction of pulse having the central wavelengths of 1.98 μm, duration of 30 fs with the electric field amplitude 100 MV/m, propagating along the optical axis is considered. The thickness of GaSe crystal in numerical simulations is 198 μm. For study the pulse dynamic spectrum evolution the smoothed pseudo Wigner distribution (SPWVD) transformation was applied. In order to increase the time and frequency resolution of the pulse dynamic spectrum the Mexican-hat wavelet based continuous wavelet transform (CWT) was applied. The dependences of SFR and DFR generation efficiency versus propagation distance inside of crystal at fixed values of initial pump pulse amplitude 10, 50 and 100 MV/m are obtained. The SFR and DFR generation efficiency dependences versus initial pump pulse amplitude are obtained. It's shown that the maximum values of SFR and DFR generation efficiencies at initial pump pulse amplitude 100 MV/m are 4.8 × 10?3% and 2.7 × 10?3% respectively.