Fig. 1. Spot patterns of different kinds of MPCs consisting of two mirrors. (a) Spot pattern of a Herriott cell^[32]; (b) spot pattern of a dual-path Herriott cell^[32]; (c) spot pattern of the astigmatic mirror cell^[46].

Fig. 2. Model calculation and TracePro simulation of spot distribution pattern of an MPC consisting of double spherical mirrors. (a) Dense spot pattern gotten by the calculation model; (b) spot pattern simulated by TracePro with the same parameters as in (a). Reprinted with permission from Ref. [48] © Optica Publishing Group.

Fig. 3. Exotic spot patterns generated by an MPC consisting of double spherical mirrors. (a) Simulated results, and the black spots surrounded by the green circles represent the exit positions of the beam; (b) photographs of the real spot patterns on the exit spherical surfaces. Reproduced from Ref. [49], with the permission of AIP Publishing.

Fig. 4. MPCs consisting of double spherical mirrors based on the vector reflection theory. (a) Three independent circle patterns-based MPCs with five, seven, and nine circles; those above are simulated patterns by using multiray tracing, while those below are the corresponding physical photographs. Reprinted with permission from Ref. [52] © Optica Publishing Group. (b) Simulated results and real photographs of MPC with high density^[51].

Fig. 5. Structure of a White cell and the spot pattern on M3. Reprinted with permission from Ref. [55] © Optica Publishing Group.

Fig. 6. MPC based on at least three spherical mirrors. (a) Beam path types in MPC based on three to six spherical mirrors; (b) structural drawings and physical photographs (the OPL is 23.8 m) of bow-tie-like MPC based on four spherical mirrors. Reprinted with permission from Ref. [55] © Optica Publishing Group.

Fig. 7. Folded MPC consisting of three spherical mirrors with off-axis placement. (a) Structure of MPC and its equivalent coaxial structure; (b) simulated results of mirror spot of the folded MPC with OPL of 97.6 m^[57].

Fig. 8. Circular prism array MPC: on the left is a detailed view of the object; on the right is a photograph of the optical path pattern observed using a 532 nm visual laser^[58].