Investigation on optomechanical accelerometer via dual heterodyne interference self-referencing testing

We introduce an optomechanical accelerometer for low-frequency acceleration detection and noise suppression, based on dual-heterodyne interference self-referencing testing. The accelerometer’s sensitive unit adopts a self-designed “dumbbell”-shaped mass-spring structure made of fused silica, with a theoretical natural frequency of 57.073 Hz. The two ends of the “dumbbell” structure form the reference interference optical system and the measurement interference optical system. Dielectric-coated high-reflectivity mirrors are attached to the structure’s ends. The accelerometer employs a dual-heterodyne interference self-referencing system and incorporates a reference interference optical system. This configuration serves to mitigate noise sources, including those originating from light sources and optical instruments, as well as environmental factors such as temperature and air pressure, improving the signal-to-noise ratio (SNR). Experimental results show that in air, the accelerometer has a noise-equivalent acceleration of 15 ng/√Hz, a 1.3-mg measurement range, and a 47-V/g scale factor. With its high SNR, small size, low cost, and simple setup, the accelerometer holds potential for aerospace, earthquake detection, and other applications.