Optical system design of imaging spectrometer with large aperture and high resolution

Abstract

In this paper, the optical design technology of wide spectrum Dyson hyperspectral imaging is studied. This study adopts the light splitting form matched with the transmission front objective lens and the Loran grating element, a kind of light splitting form with the wavelength of 430nm ～ 850nm, the relative aperture of 1/2.5 and the light passing aperture of Φ 70mm high resolution spectrometer with large relative aperture and 9.2° field of view. By analyzing the advanced chromatic aberration characteristics of wide-band imaging system, three conventional optical materials (H-K2, H-LaK5A, and H-FK61) with good physical and chemical properties are selected to correct the chromatic aberration of objective lens, and the design of image square telesyclic objective lens of wide-spectrum achromatic imaging system is achieved. Based on the theory of astigmatism elimination, the spectral structure of Dyson imaging is optimized to improve the spatial and spectral resolution of the system .The design results show that MTF of Nyquist frequency is greater than 0.8, and the design value of spectral bending is less than 2μm. The color distortion is less than 0.1%. The spectrometer has the advantages of large relative aperture, high resolution, compact structure and small size.While ensuring the high signal to noise ratio of the instrument, the design effectively solves the problem of spatial overlap of key components in the traditional Dyson hyperspectral imaging system, and can meet the engineering development requirements of hyperspectral imaging cameras, such as airborne, vehicle mounted and low orbit satellite borne cameras.