Terahertz detection using electro-optic effect in a ZnTe layered structure

In this work, a layered structure of ZnTe slabs separated by air-gaps is used to detect terahertz pulses. The structure which can be considered as a periodic structure is operating close to its stop-band edge where the transmission of the optical signal is attenuated. Applying the terahertz signal will vary the refractive index of the ZnTe slabs of the periodic structure due to the electro-optic effect in ZnTe. Consequently, the stop-band will shift in the presence of the terahertz signal. Hence, the intensity of the transmitted optical signal is modulated by the terahertz pulse, thus the terahertz signal can be detected. To examine the performance of the proposed detector, a finite-difference time-domain (FDTD) analysis is employed so that the nonlinear processes involved in the ZnTe slabs can be taken into account rigorously. Performance of the proposed structure will be compared with that of the conventional detectors based on a single ZnTe layer.