Histidine and guanadinium tetrafluoroborate: two new semiorganic frequency conversion crystals

Semiorganics are a new class of high performance nonlinear optical (NLO) materials in which a polarizable organic molecule is stoichiometrically incorporated within an inorganic host forming either an organic/ inorganic salt (e.g., DLAP1) or an organic ligand/metal ion complex (e.g., ZTS2). This design methodology offers a high degree of design flexibility and allows the linear properties, such as the refractive index and absorption characteristics, of a new material to be “engineered” to a certain extent. We have examined the second-order nonlinear optical response of over 700 such semiorganics. Two materials in this group, guanidinium tetrafluoroborate (GFB) and L-histidine tetrafluoroborate (HFB), show significant promise as a NLO crystals for the UV through the near-IR (see Fig. 1).