Fig. 1. Structure diagram of Fizeau interferometer

Fig. 2. Schematic diagram of optical path on imaging plane

Fig. 3. Structure of annular lens and the generation of ring source. (a) Structure of annular lens; (b) generation of ring source

Fig. 4. Double telecentric path used to scale a ring source

Fig. 5. Relationship between the image-space numerical aperture of double telecentric lens and the object-space numerical aperture of collimating lens

Fig. 6. Diagram of ring source system

Fig. 7. 5-fold beam expanding system. (a) 2D layout; (b) axial field of wavefront map; (c) off-axial field of wavefront map

Fig. 8. Annular lens parameters

Fig. 9. Aspheric lens. (a) Layout; (b) spot diagram

Fig. 10. Double telecentric lens

Fig. 11. Spot diagram

Fig. 12. Structure diagram of annular lens

Fig. 13. Optical system of ring source

Fig. 14. Ring source based on annular lens system

Fig. 15. Two kinds of Fizeau interferometers based on ring source illumination. (a) Ring source illumination based on binary grating; (b) ring source illumination based on annular lens