Abstract

Second-harmonic generation (SHG) and electric-field-induced SHG (FISHG) studies of PLZT thin films on fused silica substrates are reported. Our nonlinear optical studies of these materials have demonstrated that PLZT (x/0/100) with percentage concentrations of x = 7,15, and 28 offer a wide range of structural symmetry properties. The (7/0/100) composition has a tetragonal crystal structure, while (28/0/100) is nearly cubic. This increase of symmetry for compositions of x = 7 to x = 28 is experimentally observed in the decrease of SHG signals for the same compositions. On the other hand, FISHG, a third-order effect, shows the reverse behavior from field-on/field-off ratios of the signals. Furthermore, the orientation of and the nonlinearities corresponding to the c-axes of these highly oriented films, as found by varying the angle of incidence of the laser beam on the films, are reported. We have also observed a 15-fold enhancement of SHG signal, due to corona poling. From these measurements we conclude that (7/0/100) maximizes SHG, and (28/0/100) maximizes FISHG.

© 1990 Optical Society of America