title: [Optimization of broad-band flat-field holographic concave grating without astigmatism].
abstract: The desirable imaging locations of the flat-field holographic concave gratings should be in a plane. And the object can be imaged perfectly by the grating when the tangential focal curve and sagittal focal curve both superpose the intersection of the image plane and dispersion plane. But actually, the defocus can not be eliminated over the entire wavelength range, while the astigmatism vanishes when the grating parameters satisfy some conditions. An optimization method for broad-band flat-field holographic concave gratings with absolute astigmatism correction was proposed. The ray tracing software ZEMAX was used for investigating the imaging properties of the grating. And we made a comparison between spectral performance of gratings designed by this new method and that by conventional method, respectively. The results indicated that the spectral performance of gratings designed by using the absolute astigmatism correction method can be as good as gratings designed with the conventional method. And the focusing performance in the sagittal direction is much better, so that the S/N ratio can be greatly improved.
authors.affiliation: Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China. kongdapeng@yahoo.com.cn
authors.forename: Peng
authors.initials: P
authors.lastname: Kong
authors.forename: Yu-guo
authors.initials: YG
authors.lastname: Tang
authors.lastname: Bayanheshig
authors.forename: Wen-hao
authors.initials: WH
authors.lastname: Li
authors.forename: Jin-jiang
authors.initials: JJ
authors.lastname: Cui
mesh_terms: D001251:Astigmatism; D006696:Holography; D012984:Software