Author(s)

Volodymyr Grimalsky¹, Jesus Escobedo-Alatorre¹, Christian Castrejon-Martinez², Yered Gomez-Badillo¹

¹Center for Investigations on Engineering and Applied Science (CIICAp), Institute for Investigations on Basic and Applied Science (IICBA), Autonomous University of State Morelos (UAEM), Cuernavaca, Mor., Mexico.
²Tecnológico Nacional de México/Instituto Tecnológico de Zacatepec, Zacatepec, Mor., Mexico.

It is theoretically investigated the generation of higher harmonics of two-dimensional and three-dimensional terahertz electromagnetic beams in nonlinear crystals. The attention is paid to crystalline paraelectrics like SrTiO₃ under the temperatures 60 - 200 K, these crystals possess the cubic nonlinearity. The bias electric field is applied to provide the dominating quadratic nonlinearity. The initial focusing of the beams not only increases the efficiency of generation of higher harmonics, but alto makes possible to select maxima of different higher harmonics at some distances from the input. At lower temperatures the nonlinearity behaves at smaller input amplitudes, whereas at higher temperatures the harmonic generation can be observed at higher frequencies up to 1.5 THz. In three-dimensional beams the peak amplitudes of higher harmonics can be bigger than in two-dimensional beams, but the ratios of these peak values to the maximum values of the focused first harmonic are smaller than in two-dimensional beams.

Terahertz Wave Beams, Nonlinear Crystalline Paraelectrics, Different Temperatures, Generation of Harmonics, Initial Focusing

Grimalsky, V. , Escobedo-Alatorre, J. , Castrejon-Martinez, C. and Gomez-Badillo, Y. (2023) Generation of Higher Terahertz Harmonics in Nonlinear Paraelectrics under Focusing in a Wide Temperature Range. Journal of Electromagnetic Analysis and Applications, 15, 43-58. doi: 10.4236/jemaa.2023.154004.