Determination of the individual strain-optic coefficients of glass by an ultrasonic technique.

A method for determining the individual strain-optic coefficients of transparent materials is described. It utilizes a composite piezoelectric resonator inserted in one arm of a Mach-Zehnder interferometer to give rise to a time varying interference pattern. The coefficients are deduced from the modulation of the interference pattern. The Pockels elastooptic constants for several optical glasses at 6328 A have been found by this method and these values have been analyzed in terms of nonlinear polarizabilities and lattice contributions. An estimate of the nonlinear strain polarizabilities for the oxygen, sulfur, and lead ions has been obtained.