PLZT CERAMICS ELECTROOPTIC FABRY-PEROT INTERFERENCE MODULATOR WITH THERMOOPTICAL BIAS

The electrooptic modulation of high power Ar+ laser radiation with a P LZT ceramics Fabry-Perot interference reflection and transmission modu lator is described. At low intensities I-O of the incident radiation t he PLZT Fabry-Perot interferometer without any additional reflective c oatings on the surfaces (refractive index n approximate to 2.5, Fresne l reflections on the surfaces R approximate to 19%) provides modulatio n of the reflected beam in the range from 0 up to approximate to 0.45I (O), and of the transmitted beam from approximate to 0.55I(O) up to 1. 0I(O). The increase of the intensity of the incident beam causes inevi table photorefraction effects, which can be avoided in the case of pul se modulation with a sequence of bipolar pulses. The bistable behaviou r of the Fabry-Perot interferometer due to the pronounced thermooptic effect in PLZT ceramics causes a selfinstallation of the modulator wor king conditions at higher intensities (up to 1.5 W focused by a lens f = 80 mm) of the incident laser beam.