Refractive Index and Extinction Coefficient of Hg_1-xCd_xTe at 77 and 300K

We measured refractive index and extinction coefficient of n type Hg_1-xCd_xTe with the null ellipsometric spectrum method over the visible light region at 77 and 300K, and the dispersion relation at different temperature is discussed. The value of refractive index at 77K is smaller than that at 300K, and the changes of the extinction coefficient curve at 77K is also smaller than that at 300K.