Electrooptic Light Beam Deflection with Sr_0.75Ba_0.25Nb₂O₆ Prism

Abstract

An experimental investigation was performed on the electrooptic light beam deflection with a Sr 0.75 Ba 0.25 Nb 2 O 6 isosceles prism at 6328 Å. Although measured deflection angle was large ( e.g. 3m rad. for an electric field of 6 kV/cm), deflection characteristic was considerably nonlinear and what is called butterfly hysteresis loop was observed in the ferroelectric phase. Sign and magnitude of the polarization were easily changeable and the coercive field was found to be as low as 1.3 kV/cm at 33°C. The electrooptic effect is dominated by a quadratic term with respect to the polarization. The unclamped value of the quadratic electrooptic g -coefficient g 33 was determined to be 0.14 m 4 /C 2 . An electrically-induced spot distortion was observed, which was most remarkable at the polarization reversal.