| Offner imaging system was first proposed by Abe.Offner,it is a concentric triple reflex system.It was used in Offner convex grating spectrometer and relay telephoto imaging currently and has some advantages especially in the broad spectrum of remote equipment application.Therefore,In combination with Offner optical imaging system and Spatial Heterodyne Spectroscopy,the technology was used in Spatial Heterrodyne Spectroscopy,which can meet the needs of space remote sensing in hyperspectral and broad band.The Spatial Heterodyne Spectroscopy(SHS)is a new type of high-resolution spectroscopy which is developed rapidly in the 1990s,it is generally used for atmospheric trace gas measurement,atmospheric water vapour monitoring and interstellar minerals researching,and it has played an important role in the application of remote sensing.The Offner imaging system used in SHS can meet the requirement of variability in the magnification of interferometric fringe.SHS has played an important role in the application of remote sensing.In the recent years,the study of broad-band SHS and the application of the technology which become a hotspot in fields of atmospheric wind and astronomical observation.The imaging system of SHS is used to scale the interference fringes of finite distance,and its quality was directly affected by MTF,distortion and chromatic aberration,therefore,the signal to noise ration and the accuracy of the recovery spectum were dropped.At the same time,the large object numerical aperture of the imaging aystem was required by its large flux and broad grating diffraction angle ragne.Therefore,the design of imaging system is difficult,the imaging quality for SHS is very important.Compared with traditional imaging system,Offner optical imaging system has broad band,low aberration,large numerical aperture,simple structure and compactness and better space adaptability.The main work of this paper is following:(1)In combination with the characteristics and requirements of SHS,the Offner imaging system and light path structure are designed with the optical software,and the aberration was corrected.Finally,the imaging quality of system is evaluated and tolerance is analyzed.The result shows that the imaging quality can meet the imaging lens requirements of SHS.the Offner imaging system of SHS can be achieved in engineering under the level of conventional machining and assembly.(2)Comparing with the assembly adjustment,the structure of Offner imaging is designed with mechanical design software according to light path structure.The folding shaft mirror assembly,the three mirror assembly and the lens assembly used for zoom ratio were included in the system.The results of mechanical design show that the optical element requirements of the system can be meet.(3)The stray light analysis for Offner imaging system of SHS was made,then the light baffle and light vane of optical system were designed.The optical system simulation was made with stray light analysis software,and the Point Source Transmittance(PST)of the optical system was calculated,the least method is used to simulate the curve of the PST,The stray light coefficient was calculated accorading the PST.Finally,the stray light coefficient shows that the stray light suppressing level of Offner imaging system can meet the requirement of design.Offner imaging system has batter image quality,especially for deep ultraviolet,infrared and broad band application which is limited in the transmission SHS.In combination with the two technology,the optical effiency of the optical system can be improved and the hysperspectral,broad band,high throughput remote sensing detection can be meet. |
