Wavefront sensor, detection method and system based on double helix point spread function

Abstract

The invention discloses a wavefront sensor based on a double helix point spread function, a detection method, and a system. The method comprises the steps: carrying out the focusing of a to-be-detected wavefront through a microlens array, and obtaining a Gaussian lattice diagram of all apertures on the microlens array; converting the Gaussian lattice diagram into a double helix lattice diagram through a double helix point spread function system; obtaining a mixed wavefront gradient value according to the Gaussian lattice diagram and the double helix lattice diagram; carrying out the wavefront reconfiguration of the mixed wavefront gradient value, obtaining to-be-detected wavefront information, and obtaining the pixel three-dimensional space coordinate precision information after the detected wavefront passes through the microlens array in a mode of converting detected Gaussian light spots into a double helical form. The method can prevent a wavefront defocusing error from affecting the reconfiguration precision, still can obtain the high detection precision when a target object axially moves, and greatly improves the axial detection range of a sensor under the condition of guaranteeing the detection precision.

Description

technical field [0001] The invention relates to the technical field of adaptive optics, in particular to a wavefront sensor, detection method and system based on a double helix point spread function. Background technique [0002] Wavefront detection and measurement play an important role in the fields of optical components and semiconductor manufacturing as well as astronomy and aviation. Among them, the new detection technology represented by the Shack-Hartmann wavefront sensor is widely used in optical components, metal surfaces, etc. Detection and measurement of beam wavefront distortion and phase difference; the current measurement technology is mainly divided into two categories, one is the direct measurement of the wavefront shape, and the other is the measurement of the wavefront slope; their representatives are interferometer and Shack-Hartmann wavefront sensor. Since the interferometer needs to undergo strict and precise calibration, the supporting facilities are s...

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Problems solved by technology

However, when the sample is axially displaced, the image point will not be on the back focal plane after the incident wavefront passes through the microlens, resulting in a certain defocus, and the spot on the detection surface will become larger with the increase of the defocus distance [ figure 2 (b)], in this way, the error in calculating the centroid offset will increase accordingly, which will directly affect the accuracy of wavefront reconstruction

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