| The real fringe spatial heterodyne imaging spectrometer is a variant of spatial heterodyne spectrometer,with the fringe imaging optical system of the traditional spatial heterodyne spectrometer replaced by an interference structure.This structure makes the interference surface coincide with the imaging surface,thus greatly simplifying the structure of the system,and reducing the volume and weight of the interferometer.The system inherits the characteristics of high throughput,high spectral resolution and non-moving parts of the traditional spatial heterodyne spectrometer.Therefore,it can be foreseen that the system can be used as a new type of spatio-temporal combined modulation interference spectrometer,and is especially suitable for the micro satellite platform of atmospheric remote sensing.In this paper,we focus on the position of the interference surface,the energy utilization of the system,the design process of the optical system and the simulation and experiment of the system.Firstly,the basic structure and basic principle of the real fringe spatial heterodyne imaging spectrometer are introduced.In this part the relationship between the parameters of system structure and the interference fringe frequency,spectral resolution,spectral resolving power and spectral range of the system is given.According to the path and polarization characteristics of the beam propagation,the position of the interference surface and the full aperture instrument function of the system are deduced respectively.The basic expression of the acquisition of spectral information and image information in the process of system push-broom is given.Secondly,we design and analyze the real fringe spatial heterodyne imaging spectrometer.According to the relationship between the instrument parameters of the system and the parameters of optical elements,we design a system taking the measurement of the oxygen atom airglow（O[1D]630nm）as an example.The spectral range of the system is 614.1nm631.3nm,and the spectral resolution is0.87cm-1.After analyzing the position of the interference surface and the back focal length of the front lens system,the front lens system with the focal length of 150mm and the F number of 8 is designed.Compared with the traditional spatial heterodyne interferometer,the condition of the system's energy advantage is explored.And the influence of system wave plate and line polarizer's alignment error and F number of the system front lens on the system's interference light intensity and modulation are analyzed.Finally,the whole system modeling,simulation and experimental verification are carried out according to the design results.The simulation results show that the greater the F numbers is,the greater the energy is obtained,but the contrast of the interferogram edge will be reduced.Under the same F number,the energy acquired by the system with the field widened prism and the system without field widened prism is the same,but the edge contrast of the interferogram of the interferometer without the field widened prism is very low.The system can simultaneously obtain spectral data and scene information of multiple lines,so it can be used in multi-target detection.Then the experimental platform is set up to complete the verification of spectral imaging detection capability.The result shows that the system has the ability to acquire location information and spectral information of the target,and the spectral resolution of the system is 0.83 cm-1,which is superior to the design value.Also,the result confirms the practicability and reliability of the design. |
