Parameter Optimization And Error Analysis Of Type Ⅳ Concave Holographic Grating

In this paper, we make an in-depth study on parameter optimization and erroranalysis of type â…£ concave holographic grating. Firstly, concerning the study ofparameter optimization, the optical path function aberration theory and ray tracingtheory of type â…£ concave holographic grating are derived from Fermat's principle,and a new optimization function, with the introduction of aberration-balanced mind,which can avoid the weaknesses of the optical path function aberration theory, andcan improve the computational efficiency and the performance of a gratingspectrometer is established. Additionally, the expression of the image point and rootmean square optimization function of spot diagram are derived for type â…£ concaveholographic grating recorded by two spherical waves, and genetic algorithm isintroduced to solve the root mean square optimization function, which can improvespectral resolving power further, except that the aberration theory of the gratingrecorded by non-spherical waves is also studied and the optimization result is given,which provides the groundwork for the design of high-resolution type â…£ concaveholographic gratings. Secondly, concerning the parameter error analysis of type â…£concave holographic grating, a function used to evaluate the spectral band width isestablished, and the influences on spectral band width of using parameter errors andrecording parameter errors are analyzed as well as their mutual compensations,which provide the compensation methods for those parameter errors. The influenceof grating rotation errors around and translation errors along the three axes of spacecoordinate system are analyzed, finding out the more sensitive factors of type â…£concave holographic grating substrate orientation in the process of using and recording, which has an important theoretical significance for the analysis anddistribution of orientation errors in the production and assembly of the type â…£concave holographic grating. Thirdly, concerning the production of type â…£ concaveholographic grating, the theoretical models of exposure process and developingprocess are mainly analyzed with the processes of holographic grating grooveevolution simulated, and the in-situ expose and developing monitoring methods areintroduced briefly, which provide theoretical guidance for type â…£ concaveholographic grating production. Except the three aspects studied above, the designtheory of small size, wide wave-band and multi-grating monochromator is alsostudied. A small size, three-grating monochromator with a response wavelengthrange of400-2500nm is designed. The three type â…£ concave holographic gratingsused in the monochromator are optimized and the proposal of double-layer rotatingplatforms for scanning is put forward, and the influence on monochromatorperformance of type â…£ concave holographic grating parameter errors and thedouble-layer platforms structure errors are also analyzed, which lays the foundationfor the design of small size, wide wavelength band and multi-grating spectrometer.