Electro-optic properties and modulating application of langasite single crystals

The linear electro-optic properties of langasite (La3Ga5SiO14, LGS) single crystals were investigated by the phase compensation method. An electro-optic KD2PO4 (DKDP) reference crystal was placed in the same laser beam path to compensate for the phase difference induced by the LGS crystal. The linear electro-optic coefficient r11 of LGS was determined to be 1.8 × 10−12 m/V at room temperature. The linear modulation of an ultrasonic frequency signal was accomplished by the same setup with a λ/4 wave plate replacing the DKDP crystal.