| 其他摘要 | In order to develop high spectral resolution spectroscopy and carry out the key technical research on prototype instruments of hyper-spectral remote sensing, then get the ability of monitoring and testing the atmospheric composition，2012 Changchun Institute of Optics, fine mechanics and physics take on the carbon stars payload of with CO2 detector with high spatial and hyper spectral resolution. Atmospheric CO2 detector introduces the large blaze angle reflection plane grating as the core component. Diffraction efficiency of the grating play a decisive role to the energy transfer capability of the instrument, thereby affecting the detection accuracy and precision of the inversion for CO2 concentration of atmospheric CO2 detector, so atmospheric CO2 detector also made the target to its diffraction efficiency of the large-size flat grating, Related structures have reported that using a tunable laser as a light source, select several points at the grating surface in the space to measure the grating diffraction efficiency, but this method cannot achieve the full aperture efficiency in the practice working condition, and therefore cannot fully measure the diffraction efficiency of the test grating. The existing testing equipment bear the restriction of wavelength range and detection of the test grating size, cannot achieve the testing diffraction efficiency of large-size flat grating; and the testing value for large size of the grating in the existing equipment cannot accurately reflect the energy transmission performance at its work state in atmospheric CO2 detector. Meanwhile, the tester exit slit size and the detector sensitive area also limits the detecting of the flux of the testing element.Given these reasons, according to the requirement of CO2 detecting instrument to the large-scale plane grating, we deeply study the instrument in these aspects, which including the optical system design, the optics assembly method, the efficiency measurement method and the error compensation method. The chief research work on the instrument is as following. Firstly, in allusion to the working condition and the requirement of large-size grating, according to the principle of grating efficiency measurement, adopting the structure of double-monochromator to design the instrument. For the requirement of wide spectral coverage, we put forward the design of the pre-monochromator gratings group. According to the actual result of ray tracing, we know that the wide spectral coverage diffraction efficiency instrument can satisfy the efficiency measurements of large size plane grating. Secondly, because the existing detector photosensitive area is restricted, bring on the energy integral method to collect the exit flux, and validate the correctness of the measurement method. At the same time, in view of the practical problems, we analyze them theoretically according to the principle of measuring grating efficiency, and determine the adjustment method of optical elements. Thirdly, the grating efficiency obtained from the instrument is a relative value, and the measuring accuracy of its value is affected by the measurement process and the compensation method. To improve the measuring accuracy of the grating efficiency, this paper further investigates the main factors influencing the measurement accuracy, deduce the analytic expression for the change factor of beam cross section (k(θ)). And then put forward the compensation formula of improving efficiency measurement accuracy. Through embedding the compensation procedures in the measuring software, the method can get real-time results, and meet the requirement of the instrument for accurate measurements. Fourthly, through the analysis of the performance of optical system, we put forward the alignment method, with which the optical element precision alignment and the detection signal identification of the microscope can be combined. Using this method, we achieve a precise alignment for the wide spectral plane grating diffraction efficiency instrument on the basis of the double monochromator. And then, according to the measurement process of grating efficiency, the operating software is developed, which has the functions of the wavelengths calibration and scanning, the optical system alignment and testing, and the error compensation of the results. And this software provides convenience for various kinds of grating efficiency test. |
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