Fast and sensitive bolometric terahertz detection at room temperature by MEMS resonators through thermomechanical transduction

2018.06.12

Kazuhiko Hirakawa, Institute of Industrial Science, University of Tokyo

Terahertz (THz) electromagnetic spectrum draws wide attention for nondestructive and/or biocompatible sensing. In order to be widely applicable to the THz sensing, the sensors are favored to operate at room temperature, and to have high sensitivity, and fast operation speed. However, conventional room-temperature THz thermal sensors fall short of expectations in these characteristics required in various applications of THz sensing, including THz cameras. Utilizing a thermomechanical transduction scheme, we have developed an uncooled, sensitive, and fast THz bolometer by using a doubly clamped GaAs MEMS beam resonator as a sensitive thermistor. Owing to its ultra-high temperature sensitivity, the present bolometer achieves not only a high sensitivity but also an operation bandwidth of several kHz, which is ~100 times faster than other uncooled THz thermal sensors. The MEMS bolometers are fabricated by the standard semiconductor fabrication processes and are well suited for making detector arrays for realizing THz cameras.