MEASUREMENT OF CLAMPED ELECTROOPTICAL COEFFICIENTS IN CDS, CDSE, AND CDS-CDSE

Polarimeter measurements of the electrooptical response of cadmium sulphide, cadmium selenide, and of the alloy cadmium sulphide-cadmium selenide are performed at audio frequencies. The measured value of the r(c)(t) Pockels coefficient of CdSe, which is reported for the first time, is larger than that of CdS, as expected from the S-Se substitution. The electrooptical response of the CdS-CdSe alloy is smaller than that of both parent compounds, possibly due to the microscopic strains in the solid solution. A weak dependence of the electrooptical retardation on the amplitude of the applied electric field is observed, and interpreted as a Kerr contribution superimposed on the stronger Pockels effect.