Zhejiang University

National Engineering Research Center for Optical Instrumentation

Jian Bai

Lei Zhao

Jing Hou

Xiao Huang

Jia Wang

Binjie Lu

Xiangdong Zhou

Yongying Yang

Yu Cao

Bin Lin

Xiangqun Cao

Kaiwei Wang

Yibing Shen

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

Disclosed is a non-blind-area multi-view panoramic stereo imaging device. The device comprises a front lens assembly or a plane mirror, an aspheric mirror, a middle lens assembly, a panoramic block, a rear lens assembly and an image surface which are longitudinally arranged along an optical axis. The aspheric mirror comprises a central hole and an annular reflecting surface. The panoramic block comprises a front central circular transmission surface, a front reflecting surface, a front transmission surface, a rear reflecting surface and a rear transmission surface. The front reflecting surface, the front transmission surface and the rear reflecting surface are all annular surfaces. The inner edge of the front reflecting surface is connected with the edge of the front central circular transmission surface.

Non-blind-area multi-view panoramic stereo imaging device

A 4K high-resolution panoramic annular optical system includes a panoramic annular lens head unit, a subsequent lens group, and a 4K sensor (SE) that is coaxially installed. The panoramic annular lens head unit includes a first lens (PALIPAL) and a second lens (PAL). The subsequent lens group includes a third lens (RL), a fourth lens (RL), a fifth lens (RL), a sixth lens (RL), a seventh lens (RL), an eighth lens (RL), and a ninth lens (RL) that are arranged in order from an object plane to an image plane. The first lens (PAL) and the fifth lens (RL) are meniscus glass lenses with positive refractive power. The six lens (RL) and the ninth lens (RL) are meniscus glass lenses with negative refractive power, and the second lens (PAL), the fourth lens (RL), the seventh lens (RL), and the eighth lens (RL) are biconvex lenses with positive refractive power.

4K high-resolution panoramic annular optical system

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.

Device and method for detecting wavefront error by modal-based optimization phase retrieval using extended Nijboer-Zernike theory

An optical guide has at least two diffraction gratings in serial in front of a light source in order to diffract a light beam from the light source twice. The first diffraction grating could split the light beam into several parallel light beams along a first axis, and the second diffraction grating could split the light beams into several points of light along a second axis, and so on and so forth. By rotating the diffraction gratings relative to one another and by adjusting the distance between the diffraction gratings, a user of the optical guide could adjust the angle of the axis points and adjust a relative distance of the points of light relative to one another. These light beams could provide convenient guides for users in a variety of applications.

Spectrum-generation system based on multiple-diffraction optical phasometry

The present invention discloses a wavelength scanning interferometer and a method for an aspheric surface measurement. The wavelength scanning interferometer comprises a set of tunable lasers () used as a light source, a Twyman-Green interferometer used for generating interference fringes, a translation platform () used for scanning an optical path difference along an optical axis, an image card () used for converting interference data to a digital signal and transmitting the digital signal to a computer (), and a data card () used for synchronizing the actions of a CCD camera () and the translation platform (). Different from the traditional aspheric surface measurement method, the interferometer is capable of measuring a surface with a high aspheric surface degree or a wavefront, and without the need of a zero compensation mirror. In addition, the method does not need a complex and usually expensive multi-dimensional movement platform.

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Hangzhou, China

Jian Bai