JPS6446733A - Electrooptic element - Google Patents

Abstract

PURPOSE:To generate the same optical path changing angle with a lower impressed voltage by juxtaposing three electrodes successively to a nonlinear optical material and impressing the voltages between the respective electrodes in reverse directions. CONSTITUTION:The 1st electrode 1 and 3rd electrode 3 having a plane shape are provided on both side faces of the nonlinear optical material 4 and the 2nd electrode 2 having the plane shape is provided between these electrodes so that the electric fields in the reverse directions can be formed between the 1st electrode 1 and the 2nd electrode 2 and between the 2nd electrode 2 and the 3rd electrode 3. Incident light B1 advances rectilinearly as it is in the nonlinear optical material 4 and transmitted light BT is outputted when between the 1st electrode 1 and the 2nd nonlinear optical material 2 as well as between the 2nd electrode 2 and the 3rd electrode 3 are off. The difference between the refractive index n1 between the 1st electrode 1 and the 2nd electrode 2 and the refractive index n2 between the 2nd electrode 2 and the 3rd electrode increases (n1>n2) in the on state. The incident light B1 is totally reflected at the boundary face of the electrode 2 and only the reflected light BR is outputted when the incident light is above the critical angle alpha. The same optical path changing angle is thus generated by the lower impressed voltage.