Non‐centrosymmetric molybdates CsLiMoO4 and CsLiMoO4·⅓H2O: crystal growth, polymorphism, efficient Stokes and anti‐Stokes generation and cascaded self‐frequency [χ(3)(SRS) → χ(2)(SFM)] conversion effects

Abstract

AbstractNew nonlinear‐laser properties of the non‐centrosymmetric cubic crystals CsLiMoO4 and CsLiMoO4 ·⅓H2O were studied by stimulated Raman scattering spectroscopy (SRS). Multiple Stokes and anti‐Stokes generation sidebands in the visible and near‐IR under picosecond laser pumping have been observed for the first time. All recorded Raman induced lasing components were identified and attribute to two of the SRS‐promoting A1(ν1)‐stretching (ωSRS1 ≈ 925 cm–1) and E(ν2)‐bending (ωSRS2 ≈ 310 cm–1) vibration modes of the $ {\rm MoO_4^{-2} } $ units of the crystals. The estimation measurement of the steady‐state Raman gain coefficients in the near‐IR region for both first Stokes generations in the CsLiMoO4·⅓H2O crystal showed that they are not less than 3.1 cm · GW–1. Besides of high‐order Stokes and anti‐Stokes lasing in this hydrated molybdate cascaded χ(3) → χ(2) sum‐frequency mixing interaction was observed under one‐micron pumping. Large single crystals of optical quality of both compounds were grown and characterized with respect to their structure and structural stability. Ferroic phase transitions, that occur in CsLiMoO4 are suppressed in the novel compound CsLiMoO4·⅓H2O. We classify these molybdates as attractive SRS‐active crystalline materials. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)