Evaluation of the true electro-optic effect in some doped KCl crystals

The strain-optic contribution to the electro-optic effect in KCl doped with Br-, Tl+, Cd2+ and Mn2+ ions has been evaluated from the independent measurements of the photoelastic and the electrostrictive coefficients and the true electro-optic coefficients have been calculated. The relatively small electrostrictive elasto-optic contribution in these doped KCl systems has been discussed in the light of the change in the ionicity of the bonds between the impurity ions and the Cl- ions. The possible application of the systems KCl:Cd2+ and KCl:Mn2+ at high (microwave) frequencies has been discussed in comparison with KTaO 3.