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Figure 1
(a) A schematic diagram of a VLS grating on a concave substrate to achieve an excellent flat-field condition in the meridional plane within the spectral range 2–5 nm (bottom) is compared with a plane grating with constant groove density whose focal spots for the same spectral range lie in a curved line (top). (b) A change of the meridional focal curves of the spectrometer is observed when applying different meridional radii R, while the identical parameters are as follows: D0 = 24000 lines cm−1, rm = 1000 cm, ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |