[20a-H135-1~12] 3.9 Terahertz technologies

▲ [20a-H135-3] Room temperature, very sensitive terahertz bolometer using doubly clamped mechanical oscillators

〇(PC)Ya Zhang¹, Yasuyuki Watanabe¹, Suguru Hosono¹, Naomi Nagai¹, Kazuhiko Hirakawa^1,2 (1.IIS, Univ. of Tokyo, 2.INQIE, University of Tokyo)

Keywords:terahertz detector,bolometer,MEMS oscillator

We have proposed room temperature, all electrical driving and detecting, very sensitive terahertz (THz) bolometers using doubly clamped mechanical oscillators. We fabricated GaAs MEMS doubly clamped beam oscillators, which were excited and detected both by piezoelectric effect. When a heating power is applied to a NiCr film placed on the MEMS beam surface, an internal thermal stress is generated in the beam and decreases the oscillation frequency. The present device detects the shift in the resonance frequency caused by heating and works as a very sensitive bolometer. When the oscillator is driven slightly below the nonlinear regime for the mechanical oscillations, the bolometer shows a voltage responsivity over 3000 V/W, while keeping low noise spectral density of about 60 nV/Hz^-1/2, demonstrating a noise equivalent power (NEP) of about 20 pW/Hz^-1/2 at room temperature. Further improvement in NEP is expected by optimizing the sample structure.