High Conversion Efficiency in a System “Nonlinear-Optical Crystal Partially Filling the Cross Section of a Rectangular Waveguide”

It is shown that terahertz radiation (0.1-3 THz) can be effectively generated via optical rectification of femtosecond laser pulses in a system of a “nonlinear-optical crystal partially filling the cross section of a rectangular metal waveguide”. The numerical calculations for the phase-matching in LiNbO 3 , ZnTe, DAST and GaSe nonlinear optical crystals have been performed. The influence of THz radiation absorption on the efficiency of generation of coherent THz radiation in the system has been investigated.