DEVELOPMENT PRINCIPALS OF THREE -CASCADED TERAHERTZ LASER WITH GENERATION OF DIFFERENCE FREQUENCY RADIATION IN THE NONLINEAR OPTICAL CRYSTAL ZNGEP_2 FOR TERAHERTZ HOLOGRAPHY

摘要

Optical scheme of three -stage converter of middle IR range laser radiation to the terahertz (THz) radiation of range is proposed. In the first cascade the 2-micron emission in Ho:YAG laser is generated. In the second cascade it is supposed using frequency conversion of radiation of the Ho:YAG laser in ZnGeP_2 single crystal to radiation with a wavelength of~ 4-4.5 μm, and in the second cascade it is expecting of using parametric frequency conversion of the two parametric sources~ 4-4.5 μm range to the THz range by generating radiation of difference frequency in the nonlinear optical crystal ZnGeP2. Estimation of the characteristics of the output terahertz radiation is given in this paper.