Abstract: The measurement of principal refractive indices and the thermal refractive index coefficients of yttrium vanadate(YVO4)are reported in this paper.The principal refractive indices of the crystal have been measured by selfcollimating method for the wavelenths of 488nm,632.8nm,1079.5nm and 1341.4nm in the temperature range of 20-140℃.The thermal refactive index coefficients have been obtained at these wavelenths and the constants of modified Sellmeier’s equation are also obtained in the measured temperature range.The value of birefringence (Δn) of 1064nm is calculated by Sellmeier’s equation.The calculated value agrees fairly well with the value published in the paper.

Key words: The measurement of principal refractive indices and the thermal refractive index coefficients of yttrium vanadate(YVO4)are reported in this paper.The principal refractive indices of the crystal have been measured by selfcollimating method for the wavelenths of 488nm,632.8nm,1079.5nm and 1341.4nm in the temperature range of 20-140℃.The thermal refactive index coefficients have been obtained at these wavelenths and the constants of modified Sellmeier’s equation are also obtained in the measured temperature range.The value of birefringence (Δn) of 1064nm is calculated by Sellmeier’s equation.The calculated value agrees fairly well with the value published in the paper.