Analysis and Suppression of the Residual Optical Rotation Angle in NMR Sensor

As a type of atomic sensor, the residual optical rotation angle during the detection process of the nuclear magnetic resonance (NMR) sensor limits its performance improvement. By establishing the optical rotation detection signal theoretical model of the NMR sensor, the influence of the residual optical rotation angle on the signal output is analyzed. Further, the theoretical analysis indicates that adjusting the detection laser frequency based on the D1 line resonance frequency and resonance linewidth can effectively increase the scale factor and achieve suppression of residual optical rotation angle. The temperature change rate of D1 line resonance frequency and linewidth in the NMR sensor is -15.5 MHz/°C, and the linewidth coefficients are 19.9 MHz/°C, respectively. The experimental results indicate that, following the optimization of probe laser frequency, the sensitivity of the NMR sensor has significantly improved. Furthermore, the residual optical rotation angle suppression method proposed in this study demonstrates potential applicability to other atomic sensors utilizing optical rotation detection.