title: Design of a variable-line-spacing grating pattern for spectrometers based on a grating Fresnel device.
abstract: In this Letter, we propose a variable-line-spacing (VLS) grating pattern for a hybrid diffractive device termed a grating Fresnel (G-Fresnel) lens, which is used in spectrometers to improve spectral resolution over a wide spectral range. The VLS grating pattern disperses light of specific wavelengths with a different angle and position such that the aberration caused by the Fresnel surface can be compensated for. In this manner, high resolution can be achieved over a relatively wide spectral range. The VLS grating pattern is designed based on the least wave-change principle and simulated by ZEMAX. Results reveal that the VLS G-Fresnel device allows a subnanometer resolution over a spectral range of 200 nm.
authors.forename: Xinghui
authors.initials: X
authors.lastname: Li
authors.forename: Jinchao
authors.initials: J
authors.lastname: Zhang
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
authors.forename: Kai
authors.initials: K
authors.lastname: Ni
authors.forename: Jinchao
authors.initials: J
authors.lastname: Pang
authors.forename: Rui
authors.initials: R
authors.lastname: Tian