3D printed Fabry-Perot acoustic probe with a glass horn tube

Sensing an incoming acoustic signal is typically associated with absorbing the energy, perturbing the measurement and therefore causing a deformation of the sensing elements, which is mainly related to the acoustic wave pressure. Here, we demonstrated a fiber-tip based Fabry-Perot (FP) acoustic probe sensor, which was directly printed on an optical fiber tip by a two-photon 3D printing technique and assembled by a glass horn structure, which can improve the sensitivity. It showed that the sensor has a −3 dB bandwidth of 366.05 kHz at the first resonant frequency of 467.84 kHz. A low noise-limited minimum detectable pressure level of 4.71 mPa/Hz1/2@100 kHz is obtained. Due to the acoustic wave focusing property of the horn structure, the detected signal intensity can be amplified by 4 times as the sensor located at the bottom position. It demonstrates that 3D printed micro acoustic devices could be used for weak acoustic wave detection in the applications of partial discharge, photoacoustic imaging and non-destructive detection.