Optimization of Angular Distributions of Terahertz Waves Generated in Laser-Driven Nonlinear-Optical Processes

Angular distributions are studied for terahertz waves generated via three types of laser-driven non-collinear processes in nonlinear crystals, parametric difference-frequency generation, optical rectification of femtosecond laser pulses, and generation of optical-terahertz biphotons by spontaneous parametric down-conversion. The theoretical results obtained make it possible to determine the form of angular distributions inside the nonlinear crystal, as well as its evolution during transition through a silicon interface element of various shapes mounted on the side surface of the crystal.