Electro-optic transceivers for terahertz-wave applications

Abstract

Because of the reciprocal behavior of the optical rectification and the electro-optic effect in a nonlinear optical crystal, an electro-optic transceiver can alternately transmit pulsed electromagnetic radiation (optical rectification) and detect the return signal (electro-optic effect) in the same crystal. However, the optimal condition of the electro-optic transceiver may be very different from that of the spatially separated emitter and receiver. We present a detailed description of the crystal-orientation dependence of the electro-optic terahertz devices (transmitter, receiver, and transceiver). It is found that for a (110) zinc-blende electro-optical crystal, the efficiency of the electro-optic transceiver will be optimized when the angle between the polarization of the optical pump beam and the crystallographic z axis [0, 0, 1] is 26°. Meanwhile, for a (111) crystal, the angle between the optical beam and the crystallographic direction [-1, -1, 2] should be 23°. The experimental results from a (110) ZnTe transceiver verify theoretical calculations and demonstrate a direct way to optimize the working efficiency of an electro-optic terahertz transceiver.