Development of 0.14 THz high-power pulse detector with overmoded structure

Based on the hot electron effect of n-Si irradiated by high electric field, a 0.14 THz high-power terahertz pulse detector using overmoded structure is proposed and fabricated. The detector consists of a fundamental mode waveguide WR6, a tapered waveguide, an overmoded waveguide WR10, a detecting chip made of n-Si, and a bias constant current source. First, the working process of the detector is analyzed, showing that the detector can be operated in the TE₁₀ mode well, and the expression of its relative sensitivity is given. Then, the structural parameters and manufacture techniques of detecting chip are reasonably designed, and the fabrication of detecting chips and detector prototypes is accomplished. Ultimately, the validation experiments of the detector prototype are carried out in the radiation field of the 0.14 THz relativistic surface wave oscillator, which are analyzed and compared with the measured results of diode detector. The experimental results show that, the overmoded detector prototype has a response time of picoseconds-level, the relative sensitivity of about 0.12 kW-1, and the maximum enduring power of tens of watts. Therefore, the sensor could be used to directly detect 0.14 THz high-power pulses. (authors)