Stimulated Raman scattering in monoclinic non-centrosymmetric guanylurea(1 ) hydrogen phosphite (GUHP)
Abstract
Monoclinic non-centrosymmetric guanylurea(1+) hydrogen phosphite (GUHP), (NH2)2CNHCO(NH2)H2PO3, was found to be an attractive SRS-active crystal manifesting numerous χ(3)- and χ(2)-nonlinear optical interactions. In particular, with picosecond single- and dual-wavelength pumping SHG, THG (via cascaded parametric four-wave processes), high-order Stokes and anti-Stokes lasing related to the ten SRS-active phonon modes of the crystal, octave spanning χ(3)-lasing combs and cross-cascaded χ(3) χ(3) effects with different pairs of SRS-phonons were observed.
The comparative estimation of the first Stokes steady-state Raman gain coefficients in the near-IR region allows the tentative conclusion, that their values can satisfy the practical requirements for the development of Raman laser converters. All recorded Raman-induced lasing lines were identified and attributed to the χ(3)-active vibration modes of the crystal.