High-sensitivity experimental setup to measure electrooptic coefficient in nonlinear optical material

An experimental setup to measure electrooptic coefficient in nonlinear material is described. This setup consists of an optical heterodyne Mach-Zehnder interferometer. The reference modulation is obtained with an acoustooptic light modulator. The test sample is a BGO crystal. A phase modulation of 4.2 10/sup -4/ can be detected with a 10-MHz modulation frequency applied to the crystal. An electrooptic coefficient of 1 pm/V can be measured with this setup. >