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51.
Cagigal MP Canales VF Castejón-Mochón JF Prieto PM López-Gil N Artal P 《Optics letters》2002,27(1):37-39
The wave aberration of the human eye has been measured by means of a Hartmann-Shack wave-front sensor in a population of normal subjects. The set of data has been used to compute the phase distribution, the power spectrum, and the structure function for the average eye to analyze the statistics of the ocular aberration considered as a phase screen. The observed statistics fits the classical Kolmogorov model of a statistically homogeneous medium. These results can be of use in understanding the average effect of aberrations on the retinal image and can serve as a tool to analyze the consequences of ocular-aberration compensation by adaptive optics, customized ophtalmic elements, or refractive surgery. 相似文献
52.
We present a procedure for designing to control the three-dimensional light-intensity distribution near focus. Our method is based on the use of a series of figures of merit that are properly defined to describe the effect of general complex pupil functions. As a practical implementation, we have applied our method to obtain super resolving continuous smoothly varying phase-only filters. The advantages of these kinds of filters are that they do not produce energy absorption and they are easy to build with a phase-controlling device such as a deformable mirror. Results of comparisons between the performance of our method and that of other phase-filter designs are provided. 相似文献
53.
Superresolution in compensated telescopes 总被引:2,自引:0,他引:2
We present a procedure for attaining resolution beyond the diffraction limit in ground-based telescopes. This procedure is based on the use of rotationally symmetric pupil plane filters that can be easily implemented in dynamic optical devices such as a deformable mirror of an adaptive-optics system. We show that a successful application of the technique requires partial compensation for atmospheric distortion by adaptive optics. Consequently, we derive the required level of compensation as a function of the atmospheric conditions. Finally, our results are checked using simulated data. 相似文献
54.
This paper presents a numerical method for solving the two‐dimensional unsteady incompressible Navier–Stokes equations in a vorticity–velocity formulation. The method is applicable for simulating the nonlinear wave interaction in a two‐dimensional boundary layer flow. It is based on combined compact difference schemes of up to 12th order for discretization of the spatial derivatives on equidistant grids and a fourth‐order five‐ to six‐alternating‐stage Runge–Kutta method for temporal integration. The spatial and temporal schemes are optimized together for the first derivative in a downstream direction to achieve a better spectral resolution. In this method, the dispersion and dissipation errors have been minimized to simulate physical waves accurately. At the same time, the schemes can efficiently suppress numerical grid‐mesh oscillations. The results of test calculations on coarse grids are in good agreement with the linear stability theory and comparable with other works. The accuracy and the efficiency of the current code indicate its potential to be extended to three‐dimensional cases in which full boundary layer transition happens. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Casper D Becker-Szendy R Bratton CB Cady DR Claus R Dye ST Gajewski W Goldhaber M Haines TJ Halverson PG Jones TW Kielczewska D Kropp WR Learned JG LoSecco JM McGrew C Matsuno S Matthews J Mudan MS Price L Reines F Schultz J Sinclair D Sobel HW Stone JL Sulak LR Svoboda R Thornton G van der Velde JC 《Physical review letters》1991,66(20):2561-2564
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Dye ST Annis J Becker-Szendy R Bratton CB Casper D Claus R Crouch M Errede S Gajewski W Goldhaber M Haines TJ Jones TW Kielczewska D Kropp WR Learned JG LoSecco JM McGrew C Matthews J Mudan MS Price LR Reines F Schultz J Seidel S Sinclair D Sobel HW Stone JL Sulak LR Svoboda R Thornton G van der Velde JC 《Physical review letters》1989,62(18):2069-2072
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