Research On Coaxial Large Aperture Multi-spectra Channel Wavefront Measurement System

With the development of optical processing technology,the manufacturing technology of large-aperture optical components has made great progress.Large-aperture optical systems have been directly used in the fields of military,aerospace and astronomy.The large-aperture wavefront detection technology has received widespread attention.This paper designs a coaxial large-aperture multi-spectral channel wavefront measurement system.The system is mainly composed of a fore RC shrink-beam system and wavefront sensors.The design parameters of the optical system are given,the selection of optical element parameters in the system is described.The modeling and simulation of the optical system are completed by Zemax.At 0° field of view,the PV is 0.009?(RMS,?=532.8nm)and the RMS is 0.003?(RMS,?=532.8nm).At 0.05°field of view,the PV is 0.019?(RMS,?=532.8nm)and the RMS is 0.005?(RMS,?,=532.8nm).The design scheme of the mechanical system is finished,and integrated optical-mechanical-thermal analysis of the system are completed.The thermal analysis of the wavefront measurement system is completed using Patran/Nastran finite element software.The primary and secondary mirror shape are fitted with Zernike polynomials.The aberrations are analyzed using Zemax software.At the environment of-10??50?,The RMS of the wavefront measurement system is less than 0.04?(RMS,?=532.8nm).The processing method of the primary and secondary mirrors of the coaxial large-caliber multi-spectral channel wavefront measurement system is introduced.The surface shape accuracy for primary mirror is tested using the Offner compensator method.The surface shape accuracy for secondary mirror is tested using the Hindle-sphere method.The surface shape accuracy for mirrors meet the design requirement using interferometer.Based on the principle of auto-collimation detection,the system is adjusted and tested.The wavefront error of the system is 0.05?(RMS,?=532.8nm).The parameters of the large aperture and multi-spectra channel wavefront measurement system are tested,the results show that the system with an effective aperture of 450 mm has working wavelengths of 0.5?0.8?m,0.9?1.7?m and 3?5?m.At the environment of-10??50?,the system can measure wavefronts in the visible,near-infrared,and mid-infrared bands with high precision and stability,the stability of the wavefront measurement system is better than 0.05?(RMS,?=532.8nm).The aperture of the wavefront measurement system is annular.Using the Gram-Schmidt method,the annular aperture Zernike polynomial fitting is completed.The annular Zernike polynomial is used to complete the fitting and analysis of the visible,near-infrared and mid-infrared wavefronts of the wavefront measurement system.