Magnetically Controllable CuB2O4 Phase Retarder

The modification of linear birefringence through electro- and piezo-optical effects has been applied in optical devices. In contrast, the control of linear birefringence by a magnetic field is not practically utilized since conventional magnetic linear birefringence is a second-order small effect. We report an approach to control linear birefringence with a first-order optical magneto-electric effect. The effect can provide a new type of phase retarder, which is magnetically controllable and propagation-direction dependent. (C) 2008 The Japan Society of Applied Physics