Acoustic-optomechanical oscillator for low noise equivalent pressure and large broadband response acoustic sensing applications

Abstract

There is a great need for precise ultrasound sensing across science and technology fields. To meet these increasing demands, more requirements of miniaturization, high sensitivity, and broadband response to sensors have been proposed. In this work, we demonstrate and characterize an acousto-optomechanical oscillator based on a silica microbubble and employ it as an acoustic sensor. The dual oscillation modulated by acoustic wave and radiation pressure has a unique waveform that consists of slow and fast oscillation periods, similar to the common amplitude modulation. The phenomenon is modeled by the generic cavity optomechanics dispersive framework and is experimentally validated. The dual resonance enhances the response amplitude of the acoustic signal and avoids narrow working bandwidth around the resonant frequency in a traditional mechanical resonator. Finally, the ultrasensitive broadband acoustic wave sensing experiment is explored, and the sensitivity of 27.98 mV/Pa and the noise equivalent pressure of 0.89 Pa with broadband acoustic responses are achieved. This acoustic sensing method provides a promising platform for applications, such as biomedical diagnosis, industrial monitoring, and trace chemical sensing.