Crystal growth and characterization of non-centrosysmmetric polyphosphates, type III KNd(PO_3)_4 and KGd(PO_3)_4

摘要

Single crystals of KNd(PO_3)_4 (KNP) and KGd(PO_3)_4 (KGP) with P2, space group have been successfully grown by the top seeded solution growth technique from the high-temperature self-flux melts. The as-grown crystals were transparent with sizes of 14 × 28 × 20 mm~3 (KNP) and 13 × 36 × 19 mm~3 (KGP). The X-ray diffraction, infrared spectra, transmittance spectra and specific heat capacity of title compounds have been determined. Finally, we measured the second harmonic generation efficiencies while KH_2PO_4 (KDP) as reference sample, and discussed the differences of the efficiencies of the powders and the single crystals induced by preferred orientation and self-absorption of Nd~(3+).