This paper proposes a new Zernike modal gray map reconstruction algorithm used in the nematic liquid crystal adaptive optics system. Firstly, the new modal algorithm is described. Secondly, a single loop correction ex...This paper proposes a new Zernike modal gray map reconstruction algorithm used in the nematic liquid crystal adaptive optics system. Firstly, the new modal algorithm is described. Secondly, a single loop correction experiment was conducted, and it showed that the modal method has a higher precision in gray map reconstruction than the widely used slope method. Finally, the contrast close-loop correction experiment was conducted to correct static aberration in the laboratory. The experimental results showed that the average peak to valley （PV） and root mean square （RMS） of the wavefront corrected by mode method were reduced from 2.501A （λ= 633 nm） and 0.610A to 0.0334λ and 0.00845A, respectively. The corrected PV and RMS were much smaller than those of 0.173A and 0.048A by slope method. The Strehl ratio and modulation transfer function of the system corrected by mode method were much closer to diffraction limit than with slope method. These results indicate that the mode method can take good advantage of the large number of pixels of the liquid crystal corrector to realize high correction precision.展开更多
The inverse problem of determining two convection coefficients of an elliptic partial differential equation by Dirichlet to Neumann map is discussed.It is well known that this is a severely ill-posed problem with high...The inverse problem of determining two convection coefficients of an elliptic partial differential equation by Dirichlet to Neumann map is discussed.It is well known that this is a severely ill-posed problem with high nonlinearity.By the inverse scattering technique for first order elliptic system in the plane and the theory of generalized analytic functions,we give a constructive method for this inverse problem.展开更多
基金Project supported by the National Natural Science Foundation of China (Grants Nos.60736042,60578035 and 50703039)Science and Technology Cooperation Project between Chinese Academy of Sciences and Jilin Province (Grant No.2008SYHZ0005)
文摘This paper proposes a new Zernike modal gray map reconstruction algorithm used in the nematic liquid crystal adaptive optics system. Firstly, the new modal algorithm is described. Secondly, a single loop correction experiment was conducted, and it showed that the modal method has a higher precision in gray map reconstruction than the widely used slope method. Finally, the contrast close-loop correction experiment was conducted to correct static aberration in the laboratory. The experimental results showed that the average peak to valley （PV） and root mean square （RMS） of the wavefront corrected by mode method were reduced from 2.501A （λ= 633 nm） and 0.610A to 0.0334λ and 0.00845A, respectively. The corrected PV and RMS were much smaller than those of 0.173A and 0.048A by slope method. The Strehl ratio and modulation transfer function of the system corrected by mode method were much closer to diffraction limit than with slope method. These results indicate that the mode method can take good advantage of the large number of pixels of the liquid crystal corrector to realize high correction precision.
基金partly supported by the National Natural Science Foundation of China(Grant No.10271032)Shuguang Project and E-Institute of Shanghai Municipal Education Commission(N.E03004).
文摘The inverse problem of determining two convection coefficients of an elliptic partial differential equation by Dirichlet to Neumann map is discussed.It is well known that this is a severely ill-posed problem with high nonlinearity.By the inverse scattering technique for first order elliptic system in the plane and the theory of generalized analytic functions,we give a constructive method for this inverse problem.
