Design of high resolution imaging spectrometer for ocean color detection

In this paper, a visible-near infrared imaging spectrometer optical system is designed, which is used to detect seawater elements and provides a favorable monitoring means for the protection of marine resources. According to the application background of ocean color detection instruments, the index parameters of the instrument are determined, and a high resolution imaging spectrum system is designed. The front telescope system adopts an off-axis three mirror anastigmat without intermediate real image, with the focal length of 590.75mm and the entrance diameter of 118.15mm;The system comprises an innovative spectrometer design with 0.6 magnification. The de-magnifying optical design allows the telescope to operate at F#/5, while the spectrometers are built in a more compact arrangement at F#/3.The main mirror and three mirrors use Zernike Fringe Sag surface to compensate for the aberration introduced by breaking the classical Offner concentric and isometric structure. The whole optical system comprises a single telescope feeding two functionally identical spectrometers. The spectral range is 0.4-0.9μm, field of view angle is 19 °, spectral resolution is 5nm and instantaneous field of view angle is 0.048mrad, the full field of view and full band MTF is more than 0.8, which is close to the diffraction limit, the RMS radius is less than 4 μm, and the smile and keystone of the spectrometer are less than 10% pixels.