Czochralski Growth and Characterization of a Novel Nonlinear Optical Crystal Te2P2O9

ABSTRACT: A new nonlinear optical crystal Te2P2O9 (TPO) with dimensions up to 35 × 30 × 20 mm3 was grown successfully by the Czochralski method, the optimal growth parameters are determined. This crystal crystallizes in monoclinic structure, space group Cc (No. 9), with a three-dimensional framework structure that is constructed by PO4 tetrahedra and TeO5 square pyramid. The transmission spectra suggest that it can transmit well from 0.29 to 4.70 µm. Powder SHG measurements indicate TPO is phase-matchable and the SHG efficiency is about 1.3 times that of KDP. The refractive indices revealed a moderate birefringence of 0.07612−0.09662 in the wavelength range of 365.01−1013.98 nm. Thermal analysis shows that TPO has a relatively high specific heat and thermal conductivity, which indicates that TPO has a good thermal stability. The first-principles calculations and dipole moment analysis indicate optical properties mostly originate from the contribution of TeO5.