Uncooled, Fast, and High-sensitivity Terahertz Detection by Using MEMS Technologies

Abstract

The doubly clamped MEMS beam resonators have typical resonance frequencies in the range of several hundred kHz to several MHz, and high Q-factors of several thousand to ten thousand even at room temperature. We study terahertz sensing applications of MEMS resonators by utilizing the facts that 1) the mechanical resonance frequency changes very sensitively due to the thermal expansion of the beam and 2) the heat capacitance of the MEMS beam structure is very small, which is suitable for high-speed operation. In this article, we introduce a terahertz detector based on a new operation principle that reads a slight temperature rise due to terahertz absorption as a resonance frequency shift of the MEMS beam resonator fabricated with semiconductor heterostructures. We show that the present MEMS detectors are faster by 10 to 100 times than conventional room temperature thermal sensors.