Miniature fiber optic acoustic pressure sensors with air-backed graphene diaphragms

Published: March 25, 2019

Author(s)

Douglas A. Olson, Haijun H. Liu, Zhijian Zhang, Yongyao Chen, Wen Zhongshan, Yu Miao, Hyungdae Bae, Qian Dong

Abstract

We present a miniature graphene-based acoustic sensor utilizing a graphene-silver composite diaphragm covered on top of a UV-molded cavity that is directly fabricated on the tip of an optical fiber. The composite diaphragm consists of a 4-monolayer thick graphene film coated with a 5 nm thick silver layer. This unique diaphragm design can not only take the advantage of graphene’s superior mechanical properties for simultaneously achieving high mechanical sensitivity and large bandwidth, but can also help improve the graphene’s low optical reflectivity, rendering improved sensor sensitivity. Experimental results show that compared with a sensor with pure graphene diaphragm, using the graphene-silver composite diaphragm can enhance the sensitivity by three-fold, from 21.3 mV/Pa to 68.3 mV/Pa. The sensor with the composite diaphragm exhibits a large natural frequency of 20 kHz and a large damping ratio of 0.79, both of which ensure a large bandwidth.
Citation: Journal of Vibration and Acoustics-Transactions of the ASME
Volume: 141
Pub Type: Journals

Keywords

graphene, acoustic sensors, fluid-structure interaction, fiber optic sensors
Created March 25, 2019, Updated April 26, 2019