Study On Design Method Extend And Testing Technology Of Holographic Concave Gratings

As a important spectral component,holographic concave grating has some chrarcteristics with dispersion,focus,aberration corrected,no ghost line,low stray light,which has played an important role in some fields of high-resolution spectroscopy ?optical communication.As a part of the National Key Technologies R&D Program for the 11 th Five-year Plan,the research of the paper is mostly focused on design methods? exposure system precision adjustment technologies?mask fabricating craft of the holographic concave grating.Firstly,this paper systematically studies Rowland holographic gratings,flat holographic gratings and monochromator holographic gratings.Concerning the optimization of holographic concave gratings,the theory of aberration function and ray tracing are deduced,which are based on Fermat's principle.A fast optimization design method is proposed,which based on fitting the meridian focal line?the sagittal focal line and image position.At the same time,it comparatively analyzes the characteristics of aberration optimization method and point diagram optimization method.From the view of the design result and optimization time,the focal line fitting method is a faster and more effective optimization design method.Secondly,for the Rowland holographic grating,the paper comparative researchs these conditions of the coherent laser sources on or off the Rowland circle,and the both sources located the symmetry or asmmetric of the relative basement's normal.The objective function is established,and the aberration weight is reasonable distribution.For the asymmetrical frabricate pattern of two coherent light sources in the Rowland circle,the width of the spot diagram is reduced from 20 mm to 2mm in the sagittal direction.This method improves the optimization efficiency and spectral performance.Thirdly,this paper proposed an integrative design method of concave holographic grating and spherical focusing mirror.A physical model is established,included in a focusing mirror and a holographic concave grating.Then deriving the aberration coefficient expression is based on optical path function theory.Finally,by constructing the aberration correction objective function,the satisfactory design result is obtained.This method of balancing the holographic concave grating aberration and optical system aberration,in the case of ensuring the resolution of the spectral instrument,make the width of spot diagram reduce by about 4 times in sagittal direction of the image plane,Which effectively reduces the astigmatism and sagittal coma of the optical system,and improves the efficiency of the optical system.Fourthly,to meet the required manufacturing accuracy of high-quality aberration-corrected holographic gratings,we propose a Moiré alignment algorithm for the exposure system of holographic gratings.A model of holographic grating exposure system is built with multiple degrees of freedom based on optical path function theory.The whole algorithm process is given,including derived the fourth-order orthogonal polynomial of the holographic gratings,fitted aberration coefficients and optimized Levenberg–Marquardt algorithm for the exposure system's recording parameters.The experimental results verify the correctness and feasibility of the algorithm.In addition,this paper studied the optimal design and fabrication of large-aperture holographic concave gratings,which analyzed the difficulties in the design and fabrication of the grating.The grating of the exposure parameters and the groove structure is designed in detailed.To satisfy the uniform energy distribution in the exposure area,the two beams of light energy are calculated,and the spatial filter with high magnification is selected.Finally,using the exposure and development real-time detection system,a large relative aperture holographic concave grating that satisfies the design requirements is fabricated.