Modelling half-cycle pulse generation in ZnGeP₂ crystal

For the first time for a ZnGeP₂ crystal, the three-wave interaction of picosecond pulses was considered as the difference frequency generation. The group velocities and absorption of radiation were taken into account in performing a spectral analysis. The calculations of a radiation pulse were made for the following parameters of a CO₂ laser: 100-1.25 ps and 15-1100 GW cm^-2. At the 804.5 µm wavelength of difference frequency, the spectral characteristics have been obtained and the pulse power has been found as a function of crystal length. The half-cycle pulse generation is possible at a particular crystal length.