An Optical Diffraction Microphone with Active Grating Diaphragm

Abstract

AbstractWe present a new conceptual active optical microphone based on complementary metal-oxide semiconductor (CMOS) - micro electro mechanical systems (MEMS) micromachining techniques. The diaphragm of the microphone has a diffracting grating fabricated by the CMOS process with only a small number of post-processes. The active microphone actuates the diaphragm on an arbitrary frequency by electrostatic force, and detects sound waves by the light waves. From the verification experiment result, this active microphone was able to perform advanced functions, such as the amplifier effect and the detection of phase information of sound waves.