In this Letter, a low-frequency acoustic sensor based on an extrinsic Fabry–Pérot(FP) interferometer with a silicon nitride(Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N...In this Letter, a low-frequency acoustic sensor based on an extrinsic Fabry–Pérot(FP) interferometer with a silicon nitride(Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N4 membrane is deposited on an 8 mm × 8 mm × 400 μm silicon(Si) substrate. All the assembly procedures of the sensor are focused on the substrate to avoid any damage to the membrane itself, compared to general membrane transfer methods. The frequency response of the proposed sensor is discussed theoretically and experimentally demonstrated. The sensor exhibits an excellent flat response to the tested acoustic frequency range of 1 Hz to 250 Hz. The phase sensitivity is around-152 dB re 1 rad/μPa with sensitivity fluctuation less than 0.8 dB.The frequency response characteristic shows a promising potential of the sensor in low-frequency acoustic signal sensing applications.展开更多
基金supported by the National Key R&D Program of China (No. 2018YFF01011800)the National Natural Science Foundation of China (No. 61775070)the Fundamental Research Funds for the Central Universities (Nos. 2017KFYXJJ032 and 2019kfyXMBZ052)
文摘In this Letter, a low-frequency acoustic sensor based on an extrinsic Fabry–Pérot(FP) interferometer with a silicon nitride(Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N4 membrane is deposited on an 8 mm × 8 mm × 400 μm silicon(Si) substrate. All the assembly procedures of the sensor are focused on the substrate to avoid any damage to the membrane itself, compared to general membrane transfer methods. The frequency response of the proposed sensor is discussed theoretically and experimentally demonstrated. The sensor exhibits an excellent flat response to the tested acoustic frequency range of 1 Hz to 250 Hz. The phase sensitivity is around-152 dB re 1 rad/μPa with sensitivity fluctuation less than 0.8 dB.The frequency response characteristic shows a promising potential of the sensor in low-frequency acoustic signal sensing applications.
