Fig. 1. Imaging schematic of spherical crystal

Fig. 2. Imaging schematic of toroidal crystal

Fig. 3. Simulated device diagram of imaging system

Fig. 4. Comparison charts of simulated imaging results. (a) Image of spherical crystal; (b) image of toroidal crystal

Fig. 5. Comparison charts of simulated imaging spectra. (a) Imaging spectrum of spherical crystal in sagittal plane; (b) imaging spectrum of toroidal crystal in sagittal plane; (c) imaging spectrum of spherical crystal in meridional plane; (d) imaging spectrum of toroidal crystal in meridional plane

Fig. 6. Focus images of radiation source. (a) Focus image of radiation source diffracted by spherical crystal; (b) focus image of radiation source diffracted by toroidal crystal

Fig. 7. Photo of quartz toroidal crystal

Fig. 8. Backlight imaging results of quartz toroidal crystal

Fig. 9. Intensity distribution of spectrum on imaging surface