Design Of Compact Echelle Grating Spectrometer Cross-dispersion Optical System

With the development of the spectroscopy,spectrometers are applied to various fields.Science and technology require spectrometers have characteristics of small volume,broadband spectrum and high resolution,which is the advanced spectrometer development directions.The design of optical system is the decisive factor to decide whether the spectrometer can achieve the above target In this paper,we design two types cross dispersion optical path and their resolution is compared and analyzed after optical path designed in ZEMAX.The main tasks in this article include:1.The principle and the basic structure of the echelle grating spectrometer are discussed.Echelle grating has the advantages of high resolution,full band blaze,but the diffraction orders overlap seriously.According to the characteristics of echelle grating,we discussed the basic optical structure of echelle grating spectrometer.2.A folding optical path scheme of the miniaturized echelle grating spectrometer is designed.According to the basic optical path of echelle grating spectrometer,we compared a grating and a prism as the assist dispersion element,and then discussed the methods of cross dispersion.Finally,we use a transverse prism infolding cross dispersion optical path.3.The method of aberration eliminate of the optical path is studied:According to the directional derivative method,we calculated the optical path difference(OPD).By comparing the calculation values and the simulation values,we verified the method of the OPD calculation.Then,we discussed the influence of different factors of the aberration according to the calculated OPD.4.The method of using the toroidal mirror in optical path to eliminate astigmatism is developed:As known from the previous chapters,the astigmatism is an important factor affecting the quality of imaging.We studied the toroidal mirror's parameters,and designed the cross-dispersion optical path based on toroidal mirror for eliminating astigmatism.After simulation and optimization,the optical system we designed has a resolution of less than 10 pm in the range of 230-900 nm,and the optical path size is less than 400 mm.5.The cross-dispersion optical system of a parabolic mirror as collimation and imaging mirror is compared and analyzed.The optical paths are designed by ZEMAX,using a toroidal mirror and a parabolic mirror,respectively.These two types optical path with the same size are compared.Although the design results of parabolic system can be reached in the range of 230-900 nm wavelength resolution is better than 10 pm,but the toroidal mirror cross-dispersion has characteristic of eliminating astigmatism and and imaging quality is better than the parabolic mirror design results.