2018年第65回応用物理学会春季学術講演会

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一般セッション(口頭講演)

CS コードシェアセッション » CS3 3.11 フォトニック構造・現象,13.6 ナノ構造・量子現象・ナノ量子デバイスのコードシェアセッション

[18p-C301-1~15] CS3 3.11 フォトニック構造・現象,13.6 ナノ構造・量子現象・ナノ量子デバイスのコードシェアセッション

2018年3月18日(日) 13:45 〜 18:15 C301 (52-301)

浅野 卓(京大)、中岡 俊裕(上智大)

15:00 〜 15:15

[18p-C301-4] Giant enhancement in thermal responsivity of MEMS resonators by internal mode coupling

Ya Zhang1、Bochi Qiu1、Naomi Nagai1、Kazuhiko Hirakawa1,2 (1.IIS, Univ. of Tokyo、2.INQIE, University of Tokyo)

キーワード:MEMS resoantor, mode coupling, THz detector

Microelectromechanical system (MEMS)-based resonators are very attractive for sensing applications owing to their high sensitivities. Recently, we proposed an uncooled, all electrical driving and detecting, sensitive bolometer by using a doubly clamped MEMS beam resonator, which is very promising for realizing high sensitivity and fast terahertz (THz) detection at room temperature1. It has been considered that the thermal responsivity of the MEMS resonator is determined by the material and geometrical parameters of the beam and cannot be changed.
In this work, we show that the internal mode coupling can greatly improve the thermal responsivity of the MEMS resonators. When we drive a resonance mode (fL) of the beam resonator strongly in the nonlinear regime, and its frequency is exactly equal to one third of a higher resonance mode (fH), a strong internal mode resonance between fL and fH is realized through the nonlinearity of the mechanical resonator. We have found that the thermal responsivity of the MEMS resonator is suppressed when a static heat is applied to the resonator at the mode resonance. However, when we apply a dynamic heat at a particular modulation frequency to the resonator at the mode resonance, we have observed a giant enhancement in the thermal responsivity, ~20 times higher than that of the resonator without mode coupling. Furthermore, the enhancement factor of the thermal responsivity by the mode coupling can be modulated by the coupling strength between fL and fH, and the largest enhancement factor we have observed is over 2000. We explain this enhancement by the coherent energy transfer between the two strongly coupled modes. The observed effect can be widely applied to high-sensitivity sensing applications by MEMS resonators.