High-power terahertz pulse sensor with overmoded structure

Based on the hot electron effect in a semiconductor, an overmoded resistive sensor for 0.3–0.4 THz band is investigated. The distribution of electromagnetic field components, voltage standing wave ratio (VSWR), and the average electric field in the silicon block are obtained by using the three-dimensional finite-difference time-domain (FDTD) method. By adjusting several factors (such as the length, width, height and specific resistance of the silicon block) a novel sensor with optimal structural parameters that can be used as a power measurement device for high power terahertz pulse directly is proposed. The results show that the sensor has a relative sensitivity of about 0.24 kW−1, with a fluctuation of relative sensitivity of no more than ±22%, and the maximum of VSWR is 2.74 for 0.3–0.4 THz band.