Research On The Czerny-Turner Spectrometer System With Compound Anastigmatic Methods On Broad Band

As an important analytical tool,the spectrum instrument can effectively identify the characteristic spectrum of the substance.We realize the detection and analysis of the material by analyzing the spectral information.Spectrometer has been widely used in many fields because of its advantages of fast,simple,reliable,no pollution and no damage detection.Spectrometer is more and more welcomed by the market,and showing a trend of continuous development,which is caused by its convenience.Therefore,it is necessary to constantly focus on the perfection and development of the spectrometer.Aiming at the problem of the limited capacity of the Czerny-Turner structure with wide band,the influence factors of astigmatism correction are analyzed,including spectrum width,angle difference(between theoff-axis angle of collimator mirror and the off-axis angle of focusing mirror)and cylindrical lens placement.Among them,the angular difference effect of astigmatism correction is discussed,and studies the law of changes.By means of theoretical simulation and design optimization,it is proved that the system is correct and reasonable structure parameters can be obtained.A composite method is proposed to correct the astigmatism of the broadband Czerny-Turner structure spectrometer,which avoids the wide band can not be correcting at the same time.While the correction ability of the first-order reaches the limitation on wide broadband wavelength,the astigmatism opposite trend of the titled cylinder lens can compensate for the residual astigmatism in the optical system.The theoretical formula of titled angle with cylinder lens is deduced in the condition of the composite method.Simulated residual astigmatism of first-order conditions,compensation astigmatism of cylinder and compound method of astigmatism correction,and thenguide the design of optical system in the future.Combined with thecompound method of astigmatism correction,an anastigmatic Czerny-Turner structure ranging from 900 nm to 1700 nm is designedThe simulation results of Zemax show that,the design RMS is less than 14μm,modulation transmission function(MTF)is higher than 0.7 and the spectral resolution is 1.5nm at all wavelengths and full fields of view.The composite method can make sure the high spectral resolution,achieve 800 nm wide astigmatism correction in near-infrared region,and avoid energy spread.Research on compound method of anastigmatic Czerny-Turner structure,which can be effectively solved the question that the broadband astigmatism corrected simultaneouslyThemethod can be applied in structure design at other wavelength,and it is meaning for designing broadband anastigmatic optical system.