光谱成像技术研究室知识库

Holographic concave grating (HCG) spectrometer has many advantages, such as flat-spectrum, miniaturization, large aperture and high resolution. Firstly,the imaging formula of HCG is deduced based on information optics and its imaging characteristics are analyzed in both perpendicular plane to the slit and parallel plane to the slit. In the perpendicular plane, HCG spectrometer has good flat-spectrum; in the parallel plane, HCG spectrometer overcomes the spectral line bending and chromatic distortion of the traditional plane grating and realizes the straight spectral line imaging. In addition, the restriction of the intrinsic sagittal field curvature of HCG spectrometer to the field of view expanding is pointed out. According to the theoretical analysis results, it is proposed that symmetrical structure eliminates field curvature of HCG spectrometer. Then the aberration compensation spectrometer is designed and optimized with the utilization of ZEMAX software. Both traditional single-spherical-mirror HCG spectrometer with 0.4 mm slit length and aberration compensation HCG spectrometer with 8 mm slit length are designed with the same relative aperture F# of 3, spectral resolution of 20 nm/mm and spatial resolution of less than 25 μm. The results show that the field of view of the aberration compensation HCG spectrometer is successfully expanded 20 times larger than that of single-spherical-mirror HCG spectrometer. © 2018, Chinese Lasers Press. All right reserved.