Zhejiang University

Binjie Lu

Lei Zhao

Jing Hou

Jian Bai

Xiao Huang

Xiangdong Zhou

A phase retrieval detection device based on diffraction information fusion of a Fresnel zone plate (FZP) () is provided, including a laser (), an attenuation mirror (), a micro-objective (), a pinhole filter (), a collimating objective (), an element () to be detected, an FZP (), and an image acquisition device () that are sequentially arranged along a light path. The phase retrieval detection device uses the FZP () as a light beam convergent element instead of a conventional lens, and makes an acquired diffraction spot contain more diffraction information by virtue of a multi-focus characteristic of the FZP (). Based on a classical iterative phase retrieval method, a phase retrieval method based on the diffraction information fusion of the FZP () uses a diffraction light intensity distribution modulated by the FZP for retrieval to reconstruct a wider band of a wavefront to be detected.

Phase retrieval detection device and method based on diffraction information of fresnel zone plate

The present disclosure provides an apparatus and method for wavefront reconstruction based on rotationally symmetric extended structured light illumination. The apparatus includes a laser device, a neutral density filter, a microscope objective, a pinhole, a collimating lens, a beam splitter prism, a spatial light modulator, a lens to be measured, and an image acquisition device that are sequentially arranged. The method permits modulation of incident parallel light into phase grating-like structured light by using a spatial light modulator. Based on the characteristic of non-infinitely small pixel unit of the spatial light modulator, changing the modulation pattern of the spatial light modulator may result in different forms of structured light. Not only the object to be measured but also the real structured light wavefront can be recovered by acquiring diffraction spots at the focal plane and simultaneously updating the object plane and the structured light plane using an algorithm.

Apparatus and method for wavefront reconstruction based on rotationally symmetric extended structured light illumination

The disclosure provides a device for detecting a wavefront error by modal-based optimization phase retrieval using an extended Nijboer-Zernike (ENZ) theory. The detection device includes a point light source (), a half mirror (), a lens () to be tested, a plane mirror () and an image sensor (). The wavefront error of the component under test is characterized by using a Zernike polynomial, and a Zernike polynomial coefficient is solved based on an ENZ diffraction theory. The present disclosure realizes the one-time full-aperture measurement on the wavefront error of a large-aperture optical component, and can use a partially overexposed image to achieve accurate wavefront error retrieval. Meanwhile, the present disclosure overcomes the contradiction between underexposure and high signal-to-noise ratio (SNR) caused by a limited dynamic range when the image sensor () acquires an image. The detection device is simple and does not have high requirements for the experimental environment.

Growing community of inventors

Hangzhou, China

Binjie Lu