Measurement of clamped electrooptical coefficients in CdS, CdSe, and CdSCdSe

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 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.