Study on near-far ultraviolet imaging spectrometer with high resolution

Abstract

A near-far ultraviolet imaging spectrometer with high resolution is developed，which can be applied to the upper atmosphere observation in 115nm-295nm. The application demands of the corresponding remote sensing are analyzed. Because the imaging spectrum technology has been rarely utilized for the ionosphere observation in our country, we study some foreign advanced loads to apply the standard to our design. According to the analysis, the optical system of the imaging spectrometer is designed. The system includes an off-axis parabolic mirror as the telescope and Czerny-Turner structure as the imaging spectrum system. The photon counting detector is adopted to satisfy the observation for that the radiation is weak in near-far ultraviolet waveband. The receiving surface of the detector should be coated by different photocathode for better quantum efficiency in the near and far ultraviolet wavebands. The traditional Czerny-Turner system is not suit for the broadband imaging spectrometer because aberrations in the structure can’t be corrected homogeneously. The geometric analysis and 1^st order differential calculation method are introduced to improve disadvantages based on the aberration theory. We designed an example for the advanced imaging spectrometer. The results demonstrate that the modulation transfer function (MTF) in total field of view and the waveband is more than 0.6. The design has high spatial resolution and high spectral resolution. It certificates that the design theory can be applied to the near-far ultraviolet imaging spectrometer especial for upper atmosphere observation.