The influence of photothermal effect on the resonance frequency of fused silica micro hemispherical resonator

Abstract

Micro-electro mechanical system resonant gyroscope plays a more and more important role in inertial navigation. As a core sensing component of micro resonant gyroscope, fused silica micro hemispherical resonator (FS-MHR) is widely concerned because of its great performance potential. The resonance frequency is one of the important characteristic parameters of micro resonators, and laser vibration measurement technology is often used for high-precision measurement of this parameter. During the measurement process, it is inevitably affected by the interference of some light sources. To explore how light affects the resonance characteristics of FS-MHR, this paper establishes a relevant theoretical model; and verifies and analyzes the influence of the photothermal effect on the resonance characteristics of FS-MHR through simulation and experiment. Revealed the trend of temperature and resonance frequency changes over time under the same lighting conditions for uncoated and metal-coated films. The measured data shows that the resonance frequency of FS-MHR coated with the metal film is more susceptible to the influence of the photothermal effect. After 60 s of illumination, the resonance frequency will increase by 6.13 Hz, and frequency splitting will also cause a deviation fluctuation of 2.35 Hz under continuous illumination. This will introduce certain errors in the measurement results, and corresponding measures need to be taken to avoid interference from the light source.