An ultra-high sensitivity Fabry-Perot acoustic pressure sensor using a multilayer suspended graphene diaphragm

A 10 similar to 15-layer suspended graphene diaphragm was adhered onto the endface of a ferrule with a 125-mu m inner diameter by van der Waals interactions to construct a miniature ultra-high sensitivity Fabry-Perot acoustic sensor. Considering the dynamic acoustic pressure measurement, the properties of film natural frequency and optical reflectivity were investigated by ANSYS modal simulation and Fresnel's equation, respectively. The average reflectivity of the multilayer graphene diaphragm was measured to be about 1.49%. Acoustic testing demonstrated a pressure-induced deflection of 2.38 nm/Pa at 15 kHz with a nice omnidirectionality. The sensitive diaphragm structure breaks the sensitivity limitations imposed by the increased thickness and the decreased dimension of a diaphragm used in traditional Fabry-Perot pressure sensors.