Sellmeier's equation and the expression of the thermal refractive-index coefficient for a Nd_(0.007)Gd_(0.993)VO_(4) crystal

摘要

The principal refractive indices of a Nd_(0.007)Gd_(0.993)VO_(4) crystal for wavelengths of 0.488, 0.6328, 1.064, 1.0795, and 1.3414 μm under the temperature range of 20-170℃ are measured by the autocollimation method, and the Sellmeier's equation and the expression of the thermal refractive-index coefficient are then obtained. The reliability of these results is checked by comparing the calculated values with the measured values for the measured wavelengths and the temperature region, as well as with the published values by Studenikin et al. [Quantum Electron. 25, 1162-1165 (1995)] for wavelengths of 0.491, 0.546, 0.578, 0.632, 0.808, and 1.062 μm at 20℃. In addition, the birefringence and the thermal coefficient of the birefringence were obtained by measured results. The results show that the birefringence is larger than that of a YVO_(4) crystal and that the thermal coefficient of birefringence is less than that of a YVO_(4) crystal. Therefore it can be expected that the GdVO_(4) crystal is not only an excellent laser crystal but also an excellent birefringent crystal used in a modern optical transmission system as a passive fiber-optic component.