INTERFEROMETRIC INVESTIGATION OF THE QUADRATIC ELECTROOPTIC EFFECT INKDP

A Michelson interferometer was used to study the quadratic electro-opt ic effect in KDP. The values for three individual coefficients, determ ined for the first time by interferometric means, are g(1111) = -4.0, g(3311) = -0.6, and g(2211) = 0.2 (in units of 10(-20) m(2) V-2). The lattice contribution, which forms the dominant part of g(1111) and g(3 311), is discussed in terms of the bond polarizability model. The resu lts provide further evidence that the third-order bond polarizability is of comparable magnitude for crystals of different structure and com position.