SKM 2021 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 4: Poster

DS 4.9: Poster

Dienstag, 28. September 2021, 10:00–13:00, P

Tunable frequency comb in flexural-mode-coupling regime in nonlinear mechanical membrane resonators — •Mengqi Fu, Fan Yang, and Elke Scheer — Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany

Multimode coupling in mechanical systems has attracted broad interest in many realms of physics[1,2]. Recently, the research on the multimode coupling has been extended to strong nonlinear systems and novel phenomena have been observed caused by the strong nonlinearity of the coupled flexural modes[2]. Here, we demonstrate a novel tunable frequency comb generated by driving the mechanical system into the strongly nonlinear regime, i.e. the flexural-mode-coupling regime, by one-tone excitation. The studied system is based on a suspended SiN membrane (∼ 500 nm thickness) with a quality factor of ∼ 19000. The frequency separation between neighboring sidebands of the frequency comb strongly depends on the damping factor, nonlinearity, vibration amplitude and the detuning frequency of the two coupled flexural modes. The frequency separation is tunable by varying the detuning frequency and the strength of the drive power. By systematically investigating the frequency response of the fluctuations close to the coupled flexural modes, we show that the observed frequency comb is generated when the "very states"[3] produced by the nonlinearity of the coupled flexural modes are crossed experimentally.

1. A. Ganesan et al., Phys. Rev. Lett. 118, 033903 (2017).

2. F. Yang et al., Phys. Rev. Lett. 127, 014304 (2021).

3. J.S. Huber et al., Phys. Rev. X, 10, 021066 (2020).