Two-mode thermal squeezing in a mechanical resonator based on a nonlinear measurement

2020.3.23

Motoki Asano and Hiroshi Yamaguchi, NTT Basic Research Laboratories

Multiple mechanical modes in a micro/nano mechanical resonator show a random motion due to thermal fluctuation. Producing a correlation among the modes is applicable for sensing and information processing with squeezing the thermal noise. We demonstrated a novel squeezing scheme based on an optical nonlinear measurement of mechanical oscillators. So far, the noise squeezing has been performed by making a polarization in a pseudo-angular momentum with a sum-frequency pump signal. We clarified that the noise squeezing is enabled by directly observing the pseudo-angular momentum via the nonlinear measurement and filtering out the outcome. We experimentally achieved the noise squeezing with a high-Q silicon nitride mechanical resonator (quality factor of 104) by filtering out a signal from the second-order optomechanical conversion [1]. This result would be extended to controlling a mechanical resonator without any pump signals and novel measurement-feedback schemes based on information from nonlinear measurement.

[1]M. Asano, R. Ohta, T. Aihara, T. Tsuchizawa, H. Okamoto, and H. Yamaguchi “Optically probing Schwinger angular momenta in a micromechanical resonator” Phys. Rev. A 100 (5), 053801 (2019)