Enhanced acoustic sensitivity through high-Q-resonator mechanical resonance sidebands

Abstract

This paper presents a method for high-resolution and high-sensitivity detection of weak acoustic signals based on the mechanical resonance calcium fluoride (CaF 2 ) resonator. The method utilizes sideband signals generated by the coupling of the frequency of the acoustic signals to be measured and the intrinsic mechanical frequency of the resonator. At a quality factor ( Q -factor) of 1.25×10 8 , the signal-to-noise ratio (SNR) of the acoustic signal, as measured by the sensor in the 1–10 kHz frequency range, exhibits an improvement of over 20 dB in comparison to the non-resonant state. At 6 kHz, the system achieves an SNR of 75 dB, a sensitivity of 7.69 V/Pa, and a minimum detectable acoustic pressure (MDP) of 8.69µPa/Hz 1/2 .