Fig. 1. Diagram of depolarized derotator

Fig. 2. Optical path diagram of depolarized derotator alignment scheme

Fig. 3. Light pot trajectory with the rotation of optical axis around y-axis. (a) α₃=α₄=β₃=β₄=0; (b) α₃=β₃=10 arcsec, α₄=β₄=0; (c) α₃=β₃=0, α₄=β₄=10 arcsec

Fig. 4. Light pot trajectory with the rotation of M3 around x-axis and y-axis. (a) Rotation around x-axis; (b) rotation around y-axis

Fig. 5. Light pot trajectory with the rotation of M4 around x-axis and y-axis. (a) Rotation around x-axis; (b) rotation around y-axis

Fig. 6. Compensation effect when M3 and M4 rotate around y-axis

Fig. 7. Optical path diagram of alignment system in lab

Fig. 8. Principle prototype of depolarized derotator

Fig. 9. Parallel adjustment of normal of reference mirror and motor rotation axis. (a) Transmitted optical path; (b) reflected optical path

Fig. 10. Parallel adjustment of optical axis and motor rotation axis. (a) Transmitted optical path; (b) reflected optical path

Fig. 11. Concentric adjustment of optical axis and motor rotation axis.(a) Transmitted optical path; (b) reflected optical path

Fig. 12. Adjustment result of depolarized derotator

Fig. 13. Polarization test diagram of depolarized derotator

Fig. 14. Mueller matrix of depolarized derotator