Temperature Measurement of the Laser Cavity Based on Multi-Longitudinal Mode Laser Self-Mixing Effect

A method based on the self-mixing vibration sensing signal of a multi-longitudinal mode laser is found to measure the temperature of the laser cavity. In the experimental system, the temperature variation of the laser cavity can be extracted from tracking the undistorted waveforms of the superimposed multi-longitudinal mode laser self-mixing vibration sensing signal that are highly susceptible to the compensating length of the external cavity. The temperature measurement resolution of the laser cavity temperature monitoring system is 0.253 K, which corresponds to 39.49 μm/K of the external cavity sensitivity. It has also been shown that the experimental results are well consistent with the measurement of using the thermal imaging camera.