A special method for precise refractive index measurement of uniaxial optical media.

A method was developed for measuring the refractive index of optical glasses and uniaxial crystalline solids when established refractometric methods are not feasible. A synthetic ruby cuboid was contacted to a prism of known refractive index and a spectrometer was used to measure the angles describing the optical path through the ruby-glass combination. Ray tracing equations were derived to compute the refractive index accurate within 3 x 10(-5). Index values for both polarizations of ruby are given at selected wavelengths from 0.4358 microm to 0.7065 microm.