Crystal growth, crystal structure, vibrational spectroscopy, linear and nonlinear optical properties of guanidinium phosphates
Abstract
Of the three guanidinium phosphates GuH2PO4 (space group P2(1)/c), Gu2HPO4.H2O (space group P4(bar)2(1)c) and Gu3PO4.3/2 H2O (space group Cc) crystal structures and a vibrational spectroscopy study are presented. Large single crystals of GuH2PO4 and Gu2HPO4.H2O are grown.
Refractive indices and their dispersion in the wavelength range 365 nm - 1083 nm are determined and used for the analysis of phase matching conditions for collinear SHG in the case of the non-centrosymmetric crystals of Gu2HPO4.H2O. The crystals are not phase-matchable within their transmission range.
Both independent components of the SHG tensor of Gu2HPO4.H2O, determined by the Maker fringe method, are given, with d(14) = 0.23 pm/V and d(36) = 0.22 pm/V. In addition, the thermal stability and the anisotropy of thermal expansion of GuH2PO4 and Gu2HPO4.H2O is reported.