[1] [1] YANG T, ZHU J, JIN G. Nodal aberration properties of coaxial imaging systems using zernike polynomial surfaces ［J］.JOSA A, 2015, 32(5): 822-836.

[2] [2] JONATHAN C PAPA, JOSEPH M HOWARD, JANNICK P ROLLAND. Starting point designs for freeform four-mirror systems ［J］.Optic. Eng., 2018, 57(10): 101705.

[3] [3] YAO Y X, YUAN Q, CHEN L, et al.. Freeform surface design method combined with surface and field-of-view optimization ［J］. Infrared and Laser Engineering, 2018, 47(10): 1018001-1.(in Chinese)

[4] [4] BRYAN D STONE, JOSEPH M HOWARD. Low-order aberration coefficients of systems with freeform surfaces ［J］.Optic. Eng., 2018, 57(10): 101702.

[5] [5] LIU Z Y, LI L X, ZENG X F, et al.. Fabrication of large aspheric mirror using multi-mode polishing based on error separation ［J］. Opt.Precision Eng., 2017, 25(4): 814-816.(in Chinese)

[6] [6] XUE D L, ZHENG L G, ZHANG F. Off-axis three-mirror system based on freeform mirror ［J］. Opt.Precision Eng., 2011, 19(12): 2813-2818.(in Chinese)

[7] [7] SUN H, Qi J L, LIN Z X, et al.. Factors affecting the machining precision of a micro-lens array on a spherical surface in slow tool servo machining ［J］. Opt.Precision Eng., 2018, 26(10): 2517-2518.(in Chinese)

[8] [8] ZHANG X, ZHENG L G, HE X, et al.. Design and fabrication of imaging optical systems with freeform surfaces ［J］. SPIE, 2012, 8486: 848607.

[9] [9] ZHU J, WU X F, HOU W, et al.. Application of freeform surfaces in designing off-axis reflective space optical imaging systems ［J］.Spacecraft Recovery & Remote Sensing, 2016, 37(3): 1-4.(in Chinese)

[10] [10] LI R B, DU X, ZHANG ZH H. Design, Machining and Measurement Technologies of Ultra-precision Freeform Optics［M］.Beijing: China Machine Press, 2014.(in Chinese)