提出了双光栅平场全息凹面光栅光谱仪的优化设计方法。将使用波段一分为二，由两个使用结构相同的平场全息凹面光栅分别进行光谱成像以达到提高光谱分辨率的目的。根据全息凹面光栅像差理论，对光栅的使用结构和两光栅各自的制作结构进行优化求解以校正离焦、像散、彗差和球差等各种像差。据此原理设计了工作波段为200~800 nm、探测器长度25 mm的双光栅平场光谱仪。两光栅的工作波段分别为200~400 nm和400~800 nm，像面上光谱像的全宽度分别优于0.83 nm和1.68 nm。通过与相同设计指标的单光栅平场光谱仪进行比较，证明采用双光栅的设计方案能够有效地改善平场全息凹面光栅光谱仪的光谱分辨率。

The optimization method for the double-grating flat-field spectrographs which employ two aberration-corrected holographic concave gratings is described. The spectral range of the spectrograph is divided into two parts which are covered by two gratings respectively. The two gratings have the same using geometry and are fabricated with different recording geometries for the correction of aberrations, such as defocus, coma, astigmatism and spherical aberrations. A double-grating flat-field spectrograph with a wavelength range of 200~800 nm and detector length of 25 mm is designed. The spectral resolution performance is compared with a single-grating flat-field spectrograph which is designed following the same specifications. The results indicate that the spectral resolution performance can be greatly improved when the double-grating spectrograph is used.