Absolute Refractive Indices and Thermal Coefficients of Fused Silica and Calcium Fluoride Near 193 nm.

The refractive indices of several fused silica and calcium fluoride samples from different suppliers were measured with the minimum deviation method in the deep UV between 191 and 196 nm with a standard uncertainty of 7 ppm. For both materials the dispersion dn/dlambda near 193 nm and 20 degrees C was determined. In addition, we measured the thermal coefficients of the refractive index near 193 nm and between 15 and 25 degrees C.