Accuracy characterization of Shack-Hartmann sensor with residual error removal in spherical wavefront calibration  

作　　者：Yi He Mingdi Bao Yiwei Chen Hong Ye Jinyu Fan Guohua Shi 

机构地区：[1]School of Biomedical Engineering(Suzhou),Division of Life Sciences and Medicine,University of Science and Technology of China,Hefei 230026,China [2]Suzhou Institute of Biomedical Engineering and Technology,Chinese Academy of Sciences,Suzhou 215163,China [3]Center for Excellence in Brain Science and Intelligence Technology,Chinese Academy of Sciences,Shanghai 200031,China [4]Department of Ophthalmology and Vision Science,Eye and ENT Hospital,Fudan University,Shanghai 200031,China [5]Key Laboratory of Myopia of State Health Ministry,and Key Laboratory of Visual Impairment and Restoration of Shanghai,Shanghai 200031,China

出　　处：《Light(Advanced Manufacturing)》2023年第4期55-65,共11页光（先进制造）（英文）

基　　金：supported by the National Key Research and Development Program of China(2021YFF0700700);the National Natural Science Foundation of China(62075235);the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2019320);Entrepreneurship and Innovation Talents in Jiangsu Province(Innovation of Scientific Research Institutes);the Jiangsu Provincial Key Research and Development Program(BE2019682).

摘　　要：The widely used Shack-Hartmann wavefront sensor(SHWFS)is a wavefront measurement system.Its measurement accuracy is limited by the reference wavefront used for calibration and also by various residual errors of the sensor itself.In this study,based on the principle of spherical wavefront calibration,a pinhole with a diameter of 1μm was used to generate spherical wavefronts with extremely small wavefront errors,with residual aberrations of 1.0×10^(−4)λRMS,providing a high-accuracy reference wavefront.In the first step of SHWFS calibration,we demonstrated a modified method to solve for three important parameters(f,the focal length of the microlens array(MLA),p,the sub-aperture size of the MLA,and s,the pixel size of the photodetector)to scale the measured SHWFS results.With only three iterations in the calculation,these parameters can be determined as exact values,with convergence to an acceptable accuracy.For a simple SHWFS with an MLA of 128×128 sub-apertures in a square configuration and a focal length of 2.8 mm,a measurement accuracy of 5.0×10^(−3)λRMS was achieved across the full pupil diameter of 13.8 mm with the proposed spherical wavefront calibration.The accuracy was dependent on the residual errors induced in manufacturing and assembly of the SHWFS.After removing these residual errors in the measured wavefront results,the accuracy of the SHWFS increased to 1.0×10^(−3)λRMS,with measured wavefronts in the range ofλ/4.Mid-term stability of wavefront measurements was confirmed,with residual deviations of 8.04×10^(−5)λPV and 7.94×10^(−5)λRMS.This study demonstrates that the modified calibration method for a high-accuracy spherical wavefront generated from a micrometer-scale pinhole can effectively improve the accuracy of an SHWFS.Further accuracy improvement was verified with correction of residual errors,making the method suitable for challenging wavefront measurements such as in lithography lenses,astronomical telescope systems,and adaptive optics.

关 键 词：Shack-Hartmann wavefront sensor Spherical wavefront calibration Residual aberration correction High-accuracy measurement of wavefronts 

分 类 号：O43[机械工程—光学工程]