A Monoclinic Semiorganic Molecular Crystal GUHP for Terahertz Photonics and Optoelectronics

In this paper we describe the properties of the crystal of guanylurea hydrogen phosphate (NH 2 ) 2 CNHCO(NH 2 )H 2 PO 3 (GUHP) and propose its application in terahertz photonics and optoelectronics. GUHP crystal has a wide window of transparency and a high optical threshold in the visible and IR spectral regions and narrow absorption bands in the terahertz frequency range. The possibility of application of the crystal under study for the conversion of femtosecond laser radiation from visible an IR to terahertz range was demonstrated. It was shown that dispersion properties of the crystal allow the generation of narrow band terahertz radiation, whose spectral properties are determined by conditions close to phase matching. The properties of the generated terahertz radiation under various temperatures suggest the possibility of phonon mechanism of enhancement for nonlinear susceptibility of the second order.