System for improving PD (phase diversity) wave-front sensing performance

Abstract

The invention relates to a system for improving PD (phase diversity) wave-front sensing performance. The system comprises wave-front coding lens, a light splitting element, an in-focus image focal plane CCD (charge-coupled device) camera, an optical element which can be out of focus, an out-of-focus image focal plane CCD camera and a digital processing unit, wherein the wave-front coding lens and the light splitting element are arranged on the same light path; the light splitting element is used for splitting light incident into the light splitting element into reflected light and transmitted light; the in-focus image focal plane CCD camera is arranged on a light path where the transmitted light generated through the light splitting element is located; the optical element which can be out of focus and the out-of-focus image focal plane CCD camera are sequentially arranged on a light path where the reflected light generated through the light splitting element is located; the in-focus image focal plane CCD camera and the out-of-focus image focal plane CCD camera are connected with the digital processing unit respectively. According to the system for improving the PD wave-front sensing performance, the performance of a PD technology can be greatly improved, and the application fields of the PD technology are expanded.

Description

technical field [0001] The invention belongs to the field of optics and relates to a system for improving the performance of phase difference wavefront sensing. Background technique [0002] An adaptive optics system usually consists of three parts: a wavefront sensor, a wavefront corrector, and a wavefront controller. Among them, the wavefront sensor shoulders the important task of obtaining the optical wavefront distortion of the system, and is the input end of the entire adaptive optics system. Commonly used wavefront sensing technologies today include: shearing interferometers, curvature sensors, pyramidal mirror sensors, and Shack-Hartmann sensors. These techniques all require the introduction of special hardware, and some of them can only implement wavefront inversion calculations for point light sources, so they are limited in the breadth of application. At present, a new wavefront sensing technology based on image processing has become a research hotspot at home an...

AI Technical Summary

Problems solved by technology

However, this technique also has its disadvantages:

[0019] First, the dynamic range measured by classical PD technology is relatively small, and generally it can only be applied to high-precision inversion under small aberration conditions

If there is a large wavefront distortion in the system, the calculation accuracy of PD will be seriously affected

Therefore, the traditional PD technology cannot completely replace other wavefront sensing methods, and usually starts to play the role of high-precision detection after the traditional method has completed large-scale coarse-precision detection in a cascaded manner.

[0020] Second, existing studies have shown that classical PD technology requires that the relative defocus intensity introduced between positive defocus images cannot exceed 1 wavelength, which puts high demands on the optical components used to generate defocus. At the same time, the relative position accuracy of the focal plane of the positive focus optical path and the focal plane of the defocus optical path is strictly limited, because if the deviation of the relative position accuracy between the focal planes of the positive defocus imaging optical path exceeds 1 wavelength, then the PD technology will facing the possibility of failure

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