Soochow University

Yangjian Cai

Yahong Chen

Fei Wang

Zhen Dong

Deming Peng

Xi Sun

Yuechen Shen

Qidong Lin

Shilei Tan

Xiaotan Lu

Zhaofeng Huang

Chencheng Yan

Xuechun Zhao

Hu Sun

Xingyuan Lu

Zhuoyi Wang

Yonglei Liu

Chengliang Zhao

A to-be-measured partially coherent fractional vortex beam passes through a scattering object, an error between measurable information and to-be-measured information is minimized by using an optimization algorithm, and a main electric field mode and a weight of a to-be-measured fractional vortex beam are reconstructed by using a multimode stacked diffraction algorithm. A cross-spectral density function of the partially coherent fractional vortex beam is calculated, a cross-spectral density of a partially coherent fractional vortex optical field is reconstructed, and complete information including light intensity, a light intensity association, an electric field association, a phase, and the like of the partially coherent fractional vortex optical field is obtained. After the complete information of the partially coherent fractional vortex optical field is obtained, reverse transmission calculation is performed to obtain a source field vortex phase distribution, thereby implementing accurate topological charge measurement of the fractional vortex beam under low coherence conditions.

Method and apparatus for measuring topological charge of partially coherent fractional vortex beam

The invention provides a method and a system for generating a robust higher-order Poincaré sphere polarization state. The method includes: loading vortex phases into fully coherent vector beams for modulating them into left- and right-handed circularly polarized modes in a Poincaré sphere; synthesizing the left-handed and right-handed circularly polarized modes into a vector polarized light beam on the Poincaré sphere, and generating a polarization matrix of the Poincaré sphere; reducing the degree of spatial coherence of the polarized light, performing shaping to obtain a random electromagnetic beam, and simultaneously extracting polarization information in the polarization matrix and transferring the polarization information into a spatial correlation tensor of the random electromagnetic beam; and transmitting the random electromagnetic beam to a far field where the polarization information is transferred from the spatial correlation tensor into a polarization matrix of the random electromagnetic beam, to obtain a robust higher-order Poincaré sphere polarization state.

Method and system for generating a robust higher-order POINCARÉ sphere polarization state

The invention provides a method and a system for generating a polarized propagation-invariant light field. The system includes a laser source, a spatial light modulator, a computer, a first lens, a shading element, a first quarter-wave plate, a second quarter-wave plate, a second lens, and a beam combining element. In the present invention, two Laguerre-Gaussian mode beams that satisfy a particular Gouy order relationship are generated, and orthogonal even polarization is applied to the two Laguerre-Gaussian mode beams. The two Laguerre-Gaussian mode beams are then focused onto a Ronchi grating to be stably combined into polarized propagation-invariant light field. The light field generated in the present invention simultaneously has linear polarization, elliptical polarization, and circular polarization in a cross section of the light field, and in a propagation process of the light field in free space, apart from normal spot size scaling, polarization distribution remains unchanged.

Method and system for generating polarized propagation-invariant light field

An optical imaging system and a method based on spatial structure engineering of random light are disclosed. The method includes performing scattering processing on transmitted light to obtain a to-be-measured light; splitting polarization of the to-be-measured light. One light is split into x-polarized and y-polarized beams, and the other one is firstly combined with a reference beam and then split into x-polarized and y-polarized beams; measuring the intensity distributions of x-polarized and y-polarized parts of the to-be-measured light, the combined light, and the reference light; obtaining a real part and an imaginary part of the cross spectral density of the to-be-measured light, retrieving the intensity distribution of the light on the scattering medium and calculating the intensity to obtain the shape and location of the object to be measured.

Optical imaging system and method based on random light field spatial structure engineering

The invention discloses an optical imaging system and an imaging method regulated based on a spatial coherence structure, including the steps of: building a 4imaging system; detecting, by a first optical detector, the shape of the spectrum domain obstacle in the 4imaging system; designing a spatial coherence structure of the incident beam based on the shape of the spectrum domain obstacle, so that all the modes of the incident beam can pass through the opening in the obstacle; and placing an object to be detected in the optical path and detecting, by the second optical detector, the optical imaging information of the object to be detected. According to the present invention, in the case where the frequency plane of the 4optical imaging system is partially occluded, imaging without speckles is enabled, utilization of the systematic light is substantially improved, and the signal-to-noise ratio in imaging is improved.

Optical imaging system and imaging method regulated based on spatial coherence structure

The invention relates to a method for rapidly calculating a three-dimensional polarimetric dimension, including: determining that an incident light field is a coherence matrix of a partially coherent Schell-model beam, and decomposing the coherence matrix into a form of multiplying an incident electric field by a coherence structure matrix of the incident light field; obtaining an electric field near a focal field after the incident electric field passes through a tight focusing system according to the vector diffraction theory, and describing a second-order correlation characteristic of a partially coherent vector beam near a tightly focused field by using a coherence matrix; obtaining a tightly focused polarization matrix based on the tightly focused coherence matrix; and rotating the tightly focused polarization matrix into an intrinsic coordinate frame of the tightly focused polarization matrix, and calculating a three-dimensional polarimetric dimension of the partially coherent Schell-model beam in the tightly focused field.

Method for rapidly calculating three-dimensional polarimetric dimension, device, and storage medium

The invention discloses a method for measuring a complex degree of coherence of a random optical field by using a mutual intensity-intensity correlation, including the steps of: building a test optical path; rotating a quarter-wave plate to enable the fast axis of the quarter-wave plate to be consistent with a polarization direction of reference light, to obtain light intensity distribution information of a first combined light; rotating the quarter-wave plate to enable the slow axis of the quarter-wave plate to be consistent with the polarization direction of the reference light, to obtain light intensity distribution information of a second combined light; blocking the reference light to obtain light intensity distribution information of to-be-tested light; blocking the to-be-tested light to obtain light intensity distribution information of the reference light; and calculating the amplitude and phase of a complex degree of coherence of the to-be-tested light.

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Suzhou, China

Yangjian Cai