Fig. 1. Working principle diagram of four quadrant detector

Fig. 2. Energy distribution profile of an elliptical Gaussian spot

Fig. 3. Elliptical spots at different positions on four quadrant detector photosensitive surfaces

Fig. 4. The relationship between the x-axis and y-axis compensation factors and the offset angle

Fig. 5. Four orientation maps of elliptical spots on the photosensitive surface of four quadrant detectors

Fig. 6. Error in x-axis positioning algorithm for elliptical spots

Fig. 7. Error in y-axis positioning algorithm for elliptical spots

Fig. 8. Schematic diagram of spots position detection system

Fig. 9. System output power spectral density

Fig. 10. Error before and after compensation of the elliptical spot long axis (x-axis) localization algorithm at an offset angle of 45°

Fig. 11. Error before and after compensation of the elliptical spot short axis (y-axis) localization algorithm at an offset angle of 45°