ELLIPSOMETRIC INVESTIGATIONS OF PIEZO-OPTICAL EFFECTS

An introduction to the stress-induced birefringence of solids, with em phasis on cubic and amorphous materials, is given. Most available expe rimental data have been obtained in the frequency region below the ele ctronic absorption edge: the corresponding coefficients of the stress- optical tensor are then real. Above the edge (and also in the IR regio n of the Reststrahlen) they become complex. Ellipsometry is an excelle nt tool for the investigation of complex stress-optical functions. It also yields the hydrostatic pressure induced changes in the dielectric functions. Data obtained recently for diamond and zincblende-type cry stals and their theoretical interpretation are discussed. (C) 1998 Els evier Science S.A.