Fig. 1. Schematic of levitated optomechanical detection system. (a) BPD scheme; (b) QPD scheme; (c) noise model

Fig. 2. Fitting of noise PSD for single ended test and differential test

Fig. 3. Schematic of the quadrant photodetector

Fig. 4. Response calibration results of four quadrants of QPD. (a) Comparison of gain and phase differences between quadrants before and after calibration; (b) baud diagram of the frequency response of the trans-resistance circuit in each quadrant

Fig. 5. Common mode rejection effect diagram of the triaxial output of the QPD. (a) Time domain diagram of common mode rejection for 200 kHz signal; (b) CMRR measured at different frequencies

Fig. 6. Noise PSD of QPD at different input optical powers. (a) Test results of Y-axis; (b) three axes noise fitting