Relaxation Oscillations in PbLa(ZrTi)O$_{\bf 3}$ Transparent Ceramics

The relaxation optical oscillation of transparent PbLa(ZrTi)O-3 (PLZT) 10/65/35 ceramics in the far field has been observed. This is similar to that observed in Pb(Mg1/3Nb2/3)(0.9)Ti0.1O3 (PMN) ceramics. However, it is found that the oscillatory shape and the optical power required for oscillation are quite different. The transmit-ted light intensity at the beam center in the far field I-t(t) has been measured as a function of the laser power and ambient temperature. It is impossible for I-t(t) to reach the region of periodic oscillation. The oscillatory sharp can be described using cos[Sigma A(1-e(-t/tau))] which is obtained by consideration of a Fabry-Perotetalon model with temperature change after illumination. The mechanism of the oscillation is discussed.