Anomalous laser deflection phenomenon based on the interaction of electro-optic and graded refractivity effects in Cu-doped KTa1−xNbxO3 crystal

Abstract

An abnormal laser deflection phenomenon in a copper-doped KTa1−xNbxO3 (Cu:KTN) crystal is demonstrated in this Letter. A near-50 mrad beam deflection angle was observed when a voltage of 1.2 kV was applied to a Cu:KTN block with size of 2.8 mm × 1.2 mm × 7.5 mm at room temperature. The special features of this deflection phenomenon are that the laser beam deflection direction is perpendicular to the electric field direction, and the beam deflection angle remains unchanged when the electric field direction is reversed. The operating principle of the phenomenon is investigated and the origin of the deflection phenomenon is attributed to an interaction between the graded refractivity effect and the quadratic electro-optic effect of the crystal.