检索结果-南通市图书馆

Characteristics of a partially coherent Gaussian Schell-model beam propagating in slanted atmospheric turbulence

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第5期21卷 233-240页

作者：李亚清吴振森 School of Science Xidian University

On the basis of the extended Huygens-Fresnel principle and the model of the refractive-index structure constant in the atmospheric turbulence proposed by the International Telecommunication Union-Radio Communication Sector,the characteristics of the partially coherent Gaussian Schell-model（GSM） beams propagating in slanted atmospheric turbulence are studied.Using the cross-spectral density function（CSDF）,we derive the expressions for the effective beam radius,the spreading angle,and the average intensity.The variance of the angle-of-arrival fluctuation and the wander effect of the GSM beam in the turbulence are calculated numerically.The influences of the coherence degree,the propagation distance,the propagation height,and the waist radius on the propagation characteristics of the partially coherent beams are discussed and compared with those of the fully coherent Gaussian beams.

关键词： atmospheric turbulence partially coherent beam propagation in a slanted path

Scintillation of partially coherent Gaussian–Schell model beam propagation in slant atmospheric turbulence considering inner- and outer-scale effects

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第7期23卷 409-416页

作者：李亚清吴振森张元元王明军 School of Physics and Optoelectronic Engineering Xidian University School of Physics and Electronic Engineering Xianyang Normal College

Based on the modified Rytov theory and the international telecommunication union-radio （ITU-R） slant atmospheric structure constant model, the uniform scintillation index of partially coherent Gaussian-Schell model （GSM） beam propa- gation in the slant path is derived from weak- to strong-turbulence regions considering inner- and outer-scale effects. The effects of wavelength of beams and inner- and outer-scale of turbulence on scintillation are analyzed numerically. Compar- ison between the scintillation of GSM beams under the von Karman spectrum and that of beams under the modified Hill spectrum is made. The results obtained show that the scintillation index obtained under the von Karman spectrum is smaller than that under the modified Hill spectrum. This study can find theory bases for the experiments of the partially coherent GSM beam propagation through atmospheric turbulence.

关键词： atmospheric turbulence partially coherent beam scintillation atmospheric propagation

Tightly focused properties of a partially coherent radially polarized power-exponent-phase vortex beam

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第2期32卷 303-310页

作者：陈康马志远胡友友 Department of Optoelectronic Information of Science and Engineering School of ScienceJiangsu University of Science and TechnologyZhenjiang 212100China Applied Optics Research Center Jiangsu University of Science and TechnologyZhenjiang 212100China

A partially coherent beam called a radially polarized multi-Gaussian Schell-model power-exponent-phase vortex beam is introduced. Both the analytical formula of the beam propagating through the high-numerical-aperture objective lens based on the vectorial diffraction theory, and the cross-spectral density matrix of the beam in the focal region are derived. Then,the tight focusing characteristics of the partially coherent radially polarized power-exponent-phase vortex beam are studied numerically, and the intensity distribution, degree of polarization and coherence of the beams in the focusing region with different topological charge, power order, beam index and coherence width are analyzed in detail. The results show that the contour of the spot becomes clearer and smoother with the increase in the beam index, and the focal fields of different structures that include the flattened beam can be obtained by changing the coherence width. In addition, by changing the topological charge and power order, the intensity can gather to a point along the ring. These unique properties will have potential applications in particle capture and manipulation, especially in the manipulation of irregular particles.

关键词： partially coherent beam power-exponent-phase vortex beam tight focusing properties

Fractional Fourier transform for partially coherent beam in spatial-frequency domain

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2004年第7期13卷 1025-1032页

作者：蔡阳健林强 OpticsInstitute DepartmentofPhyslcsZhejlangUniversityHangzhou310027China

By using Fourier transform and the tensor analysis method, the fractional Fourier transform (FRT) in the spatialfrequency domain for partially coherent beams is derived. Based on the FRT in the spatial-frequency domain, an analytical transform formula is derived for a partially coherent twisted anisotropic Gaussian-Schell model (GSM) beam passing through the FRT system. The connections between the FRT formula and the generalized diffraction integral formulae for partially coherent beams through an aligned optical system and a misaligned optical system in the spatialfrequency domain are discussed, separately. By using the derived formula, the intensity distribution of partially coherent twisted anisotropic GSM beams in the FRT plane are studied in detail. The formula derived provide a convenient tool for analysing and calculating the FRTs of the partially coherent beams in spatial-frequency domain.

关键词： fractional Fourier transform partially coherent beam spatial-frequency domain

Design of phase plates for shaping partially coherent beams by simulated annealing

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2008年第5期17卷 1840-1844页

作者：李建龙吕百达 Institute of Laser Physics and Chemistry Sichuan University

Taking the Gaussian Schell-model beam as a typical example of partially coherent beams, this paper applies the simulated annealing （SA） algorithm to the design of phase plates for shaping partially coherent beams. A flow diagram is presented to illustrate the procedure of phase optimization by the SA algorithm. Numerical examples demonstrate the advantages of the SA algorithm in shaping partially coherent beams. An uniform flat-topped beam profile with maximum reconstruction error RE 〈 1.74% is achieved. A further extension of the approach is discussed.

关键词： partially coherent beam phase plate simulated annealing （SA）. beam shading

Coherence vortices of partially coherent beams in the far field

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2007年第2期16卷 411-415页

作者：刘普生吕百达 Institute of Laser Physics and Chemistry Sichuan University Chengdu 610064 China

Based on the propagation law of cross-spectral density function, studied in this paper are the coherence vortices of partially coherent, quasi-monochromatic singular beams with Gaussian envelope and Schell-model correlator in the far field, where our main attention is paid to the evolution of far-field coherence vortices into intensity vortices of fully coherent beams. The results show that, although there are usually no zeros of intensity in partially coherent beams with Gaussian envelope and Schell-model correlator~ zeros of spectral degree of coherence exist. The coherence vortices of spectral degree of coherence depend on the relative coherence length, mode index and positions of pairs of points. If a point and mode index are kept fixed, the position of coherence vortices changes with the increase of the relative coherence length. For the low coherent case there is a circular phase dislocation. In the coherent limit coherence vortices become intensity vortices of fully coherent Laguerre-Gaussian beams.

关键词： singular optics coherence vortex in the far field partially coherent beam Schell-modelcorrelator Gaussian envelope

Non-Gaussian statistics of partially coherent light in atmospheric turbulence

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第6期29卷 54-59页

作者：倪昊梁春豪王飞陈亚红 Sergey APonomarenko 蔡阳健 School of Physical Science and Technology&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215006China Shandong Provincial Engineering and Technical Center of Light Manipulation&Shandong Provincial Key Laboratory of Optics and Photonic Device School of Physics and ElectronicsShandong Normal UniversityJinan 250014China Department of Electrical and Computer Engineering Dalhousie UniversityHalifaxNova ScotiaB3J 2X4Canada Department of Physics and Atmospheric Science Dalhousie UniversityHalifaxNova ScotiaB3H 4R2Canada

We derive theoretically and verify experimentally a concise general expression for the normalized intensity correlations(IC)of partially coherent light in a weak atmospheric turbulence in the fast detector measurement regime.The derived relation reveals that the medium turbulence acts,in general,as an additional noise source enhancing the IC of partially coherent beams.The maximum of the beam IC is,in general,enhanced,causing the fields to exhibit super-Gaussian statistics.On the other hand,the relation indicates that turbulence-induced noise is negligible for sufficiently low coherence light,which reveals the condition for the turbulence-free correlation imaging.

关键词： partially coherent beam atmospheric turbulence intensity correlation