PLZT ceramics electrooptic fabry-perot interference modulator with thermooptic bias

The electrooptic modulation of high power Ar⁺ laser radiation with a PLZT ceramics Fabry-Perot interference reflection and transmission modulator is described. At low intensities I_o of the incident radiation the PLZT Fabry-Perot interferometer without any additional reflective coatings on the surfaces (refractive index n ≈ 2.5, Fresnel reflections on the surfaces R ≈ 19%) provides modulation of the reflected beam in the range from 0 up to ≈0.45I_o, and of the transmitted beam from ≈0.55I_o up to 1.0I_o. The increase of the intensity of the incident beam causes inevitable photorefraction effects, which can be avoided in the case of pulse modulation with a sequence of bipolar pulses. The bistable behaviour of the Fabry-Perot interferometer due to the pronounced thermooptic effect in PLZT ceramics causes a selfinstallation of the modulator working conditions at higher intensities (up to 1.5 W focused by a lens f = 80 mm) of the incident laser beam.