Structure, thermal and optical properties of Ca₉Y_0·5La_0·5(VO₄)₇ – potential nonlinear optical material

Abstract

The structure of a new nonlinear optical crystal, Ca₉Y_0·5La_0·5(VO₄)₇, was solved, for first time to our knowledge. It belongs to trigonal system with space group R3c, its unit-cell parameters are: a = 10·8717(2) Å, c = 38·0753(14) Å, V = 3897·34(18) ų, Z = 6, d_c = 6·3279 g cm⁻³. The thermal expansion, the special heat capacity and the thermal conductivity of the crystal were investigated in detail. The crystal’s relative intensity for second harmonic generation is about 1·8 times as large as that of KH₂PO₄. Its transmittance exceeds 70% in the range of 400–2700 nm. From the measured principal refractive indices, the Sellmeier equations were derived. The results show that Ca₉Y_0·5La_0·5(VO₄)₇ is expected to be a promising new frequency-doubling laser crystal.

Keywords:

• Optical material
• Crystal structure
• Optical properties
• Thermal properties

Acknowledgements

This work is supported by the National Natural Science Foundation of China (Grant No. 61275177, No. 51302260) and the National Natural Science Foundation of Fujian Province (Grant No. 2012I0011).