Modeling And Optimization Of Recording Optics For Varied Line Spacing Holographic Gratings

Diffraction gratings are the important diffractive elements in spectral instruments and their aberrations directly decide the spectral resolution. With the increasing requirement of spectral performance, varied-line-spacing gratings have been the key elements of high-resolution spectral instruments due to the excellent self-focusing and aberration-correction ability.Compared to the conventional mechanically ruled gratings, varied-line-spacing holographic gratings (VLSHGs) fabricated by holographic recording methods take the advantages of high fabrication efficiency and low stray light. Currently, VLSHGs have been widely applied to the areas such as synchrotron radiation, spatial spectrum, plasma physics, surface metrology, and so on. In both theoretical and practical aspects, it is a significant topic to study the design, fabrication and detection technologies of VLSHGs.The key point of this thesis is the design of recording optics of VLSHGs, including modeling and optimization of recording optics. The objective of modeling is to establish the relationship between recording parameters and grating parameters, while the objective of optimization is to provide proper recording parameters to meet the requirement of grating parameters.In the modeling of recording optics, the main contents of this thesis are: deriving the fourth-order analytical model for the recording optics with auxiliary spherical mirrors and auxiliary uniform-line-spacing plane gratings, providing the numerical ray-tracing models based on Fermat's principle and local search, and analyzing the expansion errors of analytical models.In the optimization of recording optics, the main contents of this thesis are: studying several forms of optimal design problems based on evolutionary algorithms for these kinds of non-linear, multimodal, and constrained complicated optimization problems, including:...