Optical system design of a femi-class ultra-high-resolution spectrometer based on the quaternary dispersion of a middle echelon grating

In order to meet the needs of the femi-ultra-high spectral resolution test, an optical system of the femi-ultra-high spectral resolution spectrometer in the spectral range of 190-800 nm is designed based on the quaternary dispersion of the middle echelon grating under the condition that the volume and weight of the spectrometer do not increase sharply. After the optimization design, the spectral resolution can reach 51.149 fm in the full field of view of 0.5 mm; at the wavelength of 191 nm, the spectral resolution in the whole spectral range is better than 150 fm, and the maximum distortion of the system is 0.2288%, which can provide a feasible reference for the subsequent design of the spectrometer optical system to realize the simultaneous detection of a wide band and high spectral resolution.