| Summary: | 碩士 === 元智大學 === 光電工程研究所 === 98 === For a single concave grating system, light received by a concave grating is limited due to its narrow acceptance angle. By adding a concave mirror as a collimator for the grating, we are able to increase the light acceptance angle from the slit, and thus increase the photon flux incident into the grating. In this study, a parabolic mirror is used as a light collecting and collimating device, which turns a divergent light source into a parallel. Based on such a design, we study the effects of the sagittal divergent angles and different slit sizes on the light collection efficiency and the spectral resolution. The study shows an enhancement in the light intensity of such a system as compared to a single concave grating, as much as 40 times in certain cases. To maintain a better spectral resolution, the slit size has to be limited within a certain range.
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