Abstract-Passive terahertz imaging detectors based on antenna-coupled high-electron-mobility transistors

Jiandong Sun, Yifan Zhu, Wei Feng, Qingfeng Ding, Hua Qin, Yunfei Sun, Zhipeng Zhang, Xiang Li, Jinfeng Zhang, Xinxing Li, Yang Shangguan, and Lin Jin

 (a) Scanning-electron micrograph of the detector with schematic measurement circuitry. (b) Zoom-in view of the central active region including the gate and the field-effect channel. (c, d) Backside and front-side views of the silicon hyperhemispherical lens with a detector chip assembled on the planar surface in a liquid nitrogen dewar with a TPX window.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-28-4-4911

Aiming at the requirement of passive terahertz imaging, we report a high-sensitivity terahertz detector based on an antenna-coupled AlGaN/GaN high-electron-mobility transistor (HEMT) at 77 K without using low-noise terahertz amplifier. The measured optical noise-equivalent power and the noise-equivalent temperature difference of the detector were about 0.3pW/Hz−−−√$0.3\mathrm{p}\mathrm{W}/\sqrt{\mathrm{H}\mathrm{z}}$ and 370 mK in a 200 ms integration time over a bandwidth of 0.7 − 0.9 THz, respectively. By using this detector, we demonstrated passive terahertz imaging of room-temperature objects with signal-to-noise ratio up to 13 dB. Further improvement in the sensitivity may allow passive terahertz imaging using AlGaN/GaN-HEMT at room temperature.

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