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Zhang Y, Cai Y, Gbur G. Switch of orbital angular momentum flux density of partially coherent vortex beams. OPTICS EXPRESS 2023; 31:38004-38012. [PMID: 38017918 DOI: 10.1364/oe.503442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/03/2023] [Indexed: 11/30/2023]
Abstract
We investigate the orbital angular momentum (OAM) flux density of beams which are the incoherent superposition of partially coherent vortex (PCV) beams with different topological charges and beam widths. Simulation results show that such beams can exhibit counter-rotating radial regions of the OAM flux density, and that we can "switch" the order of these regions by adjusting the topological charges and beam widths in the source plane. Furthermore, these counter-rotating regions can switch on propagation in free space without any change to the beam parameters. We discuss how these unusual OAM dynamics may find use in OAM-based applications.
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Xu J, Gbur G, Visser TD. Generalization of Malus' law and spatial coherence relations for linear polarizers and non-uniform polarizers. OPTICS LETTERS 2022; 47:5739-5742. [PMID: 37219317 DOI: 10.1364/ol.474267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/11/2022] [Indexed: 05/24/2023]
Abstract
We study the transmission of partially polarized, partially coherent beams through linear polarizers and polarization elements that are non-uniform. An expression for the transmitted intensity, which reproduces Malus' law for special cases, is derived, as are formulas for the transformation of spatial coherence properties.
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Dong Z, Huang Z, Chen Y, Wang F, Cai Y. Measuring complex correlation matrix of partially coherent vector light via a generalized Hanbury Brown-Twiss experiment. OPTICS EXPRESS 2020; 28:20634-20644. [PMID: 32680119 DOI: 10.1364/oe.398185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 06/20/2020] [Indexed: 05/28/2023]
Abstract
We introduce an effective method for measuring the spatial distribution of complex correlation matrix of a partially coherent vector light field obeying Gaussian statistics by extending our recently advanced generalized Hanbury Brown-Twiss experiment. The method involves a combination of the partially coherent vector light with a pair of fully coherent reference vector fields and a measurement of the intensity-intensity cross-correlation of the combined fields. We show the real and imaginary parts of the complex correlation matrix can be recovered through a judicious control of the phase delay between two reference fields. We test the feasibility of our method by measuring the complex correlation matrix of a specially correlated radially polarized vector beam and we find the consistence between the experimental results and our general theory. We further show that our complex correlation matrix measurement can be used in reconstructing the polarization states hidden behind a thin-layer diffuser.
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Schouten HF, Fischer DG, Visser TD. Coherence modification and phase singularities on scattering by a sphere: Mie formulation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2019; 36:2005-2010. [PMID: 31873372 DOI: 10.1364/josaa.36.002005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/21/2019] [Indexed: 06/10/2023]
Abstract
When light that is spatially partially coherent, such as sunlight, is incident on a sphere, the scattered field exhibits surprising coherence properties. The observed oscillatory behavior with deep minima means that the field in certain pairs of directions is highly correlated, whereas in others, it is essentially uncorrelated, and can even have correlation singularities. Because any subsequent scattering event is strongly affected by the state of coherence, these results are particularly important for multiple scattering in discrete disordered media.
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Zhang Y, Cai Y, Gbur G. Control of orbital angular momentum with partially coherent vortex beams. OPTICS LETTERS 2019; 44:3617-3620. [PMID: 31368926 DOI: 10.1364/ol.44.003617] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/06/2019] [Indexed: 06/10/2023]
Abstract
We investigate the orbital angular momentum of partially coherent beams which are constructed by a superposition of mutually incoherent vortex modes, each mode having a different beam width and topological charge. It is shown that these simple beams nevertheless provide great flexibility in controlling orbital angular momentum through adjustment of the beam parameters and have significant potential for particle rotation and trapping.
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Efimov A. Coherence and speckle contrast at the output of a stationary multimode optical fiber. OPTICS LETTERS 2018; 43:4767-4770. [PMID: 30272735 DOI: 10.1364/ol.43.004767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
We relate classic coherence properties of light at the output of a multimode optical fiber excited by a spatially coherent broadband source to speckle contrast measured by two different methods. Speckle contrast measured with an external diffuser is related to the effective number of modes, while that measured over the ensemble of random bends and twists of the fiber is related to the residual coherence defined as a spatial average of the modulus of the classic complex degree of coherence between pairs of widely separated points at the fiber output.
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Pang X, Gbur G, Visser TD. Cycle of phase, coherence and polarization singularities in Young's three-pinhole experiment. OPTICS EXPRESS 2015; 23:34093-34108. [PMID: 26832065 DOI: 10.1364/oe.23.034093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
It is now well-established that a variety of singularities can be characterized and observed in optical wavefields. It is also known that these phase singularities, polarization singularities and coherence singularities are physically related, but the exact nature of their relationship is still somewhat unclear. We show how a Young-type three-pinhole interference experiment can be used to create a continuous cycle of transformations between classes of singularities, often accompanied by topological reactions in which different singularities are created and annihilated. This arrangement serves to clarify the relationships between the different singularity types, and provides a simple tool for further exploration.
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Zhang Y, Cui Y, Wang F, Cai Y. Correlation singularities in a partially coherent electromagnetic beam with initially radial polarization. OPTICS EXPRESS 2015; 23:11483-11492. [PMID: 25969243 DOI: 10.1364/oe.23.011483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have investigated the correlation singularities, coherence vortices of two-point correlation function in a partially coherent vector beam with initially radial polarization, i.e., partially coherent radially polarized (PCRP) beam. It is found that these singularities generally occur during free space propagation. Analytical formulae for characterizing the dynamics of the correlation singularities on propagation are derived. The influence of the spatial coherence length of the beam on the evolution properties of the correlation singularities and the conditions for creation and annihilation of the correlation singularities during propagation have been studied in detail based on the derived formulae. Some interesting results are illustrated. These correlation singularities have implication for interference experiments with a PCRP beam.
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Shi L, Yuan X, Zhang Y, Hakala T, Yin S, Han D, Zhu X, Zhang B, Liu X, Törmä P, Lu W, Zi J. Coherent fluorescence emission by using hybrid photonic-plasmonic crystals. LASER & PHOTONICS REVIEWS 2014; 8:717-725. [PMID: 25793015 PMCID: PMC4358154 DOI: 10.1002/lpor.201300196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 05/26/2014] [Accepted: 05/26/2014] [Indexed: 05/21/2023]
Abstract
The spatial and temporal coherence of the fluorescence emission controlled by a quasi-two-dimensional hybrid photonic-plasmonic crystal structure covered with a thin fluorescent-molecular-doped dielectric film is investigated experimentally. A simple theoretical model to describe how a confined quasi-two-dimensional optical mode may induce coherent fluorescence emission is also presented. Concerning the spatial coherence, it is experimentally observed that the coherence area in the plane of the light source is in excess of 49 μm2, which results in enhanced directional fluorescence emission. Concerning temporal coherence, the obtained coherence time is 4 times longer than that of the normal fluorescence emission in vacuum. Moreover, a Young's double-slit interference experiment is performed to directly confirm the spatially coherent emission. This smoking gun proof of spatial coherence is reported here for the first time for the optical-mode-modified emission.
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Affiliation(s)
- Lei Shi
- Department of Physics, Key Laboratory of Micro & Nano Photonic Structures (MOE) and Key Laboratory of Surface Physics, Fudan UniversityShanghai 200433, P. R. China
- COMP Centre of Excellence, Department of Applied Physics, Aalto UniversityFI-00076 Aalto, Finland
- *Corresponding author: e-mail: , , , ,
| | - Xiaowen Yuan
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences200083 Shanghai, China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology430074 Wuhan, China
| | - Yafeng Zhang
- Department of Physics, Key Laboratory of Micro & Nano Photonic Structures (MOE) and Key Laboratory of Surface Physics, Fudan UniversityShanghai 200433, P. R. China
| | - Tommi Hakala
- COMP Centre of Excellence, Department of Applied Physics, Aalto UniversityFI-00076 Aalto, Finland
| | - Shaoyu Yin
- COMP Centre of Excellence, Department of Applied Physics, Aalto UniversityFI-00076 Aalto, Finland
| | - Dezhuan Han
- Department of Physics, Key Laboratory of Micro & Nano Photonic Structures (MOE) and Key Laboratory of Surface Physics, Fudan UniversityShanghai 200433, P. R. China
| | - Xiaolong Zhu
- Department of Physics, Key Laboratory of Micro & Nano Photonic Structures (MOE) and Key Laboratory of Surface Physics, Fudan UniversityShanghai 200433, P. R. China
| | - Bo Zhang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences200083 Shanghai, China
- *Corresponding author: e-mail: , , , ,
| | - Xiaohan Liu
- Department of Physics, Key Laboratory of Micro & Nano Photonic Structures (MOE) and Key Laboratory of Surface Physics, Fudan UniversityShanghai 200433, P. R. China
- *Corresponding author: e-mail: , , , ,
| | - Päivi Törmä
- COMP Centre of Excellence, Department of Applied Physics, Aalto UniversityFI-00076 Aalto, Finland
| | - Wei Lu
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences200083 Shanghai, China
- *Corresponding author: e-mail: , , , ,
| | - Jian Zi
- Department of Physics, Key Laboratory of Micro & Nano Photonic Structures (MOE) and Key Laboratory of Surface Physics, Fudan UniversityShanghai 200433, P. R. China
- *Corresponding author: e-mail: , , , ,
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Wu G, Visser TD. Hanbury Brown-Twiss effect with partially coherent electromagnetic beams. OPTICS LETTERS 2014; 39:2561-2564. [PMID: 24784045 DOI: 10.1364/ol.39.002561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We derive expressions that allow us to examine the influence of different source parameters on the correlation of intensity fluctuations (the Hanbury Brown-Twiss effect) at two points in the same cross section of a random electromagnetic beam. It is found that these higher-order correlations behave quite differently than the lower-order amplitude-phase correlations that are described by the spectral degree of coherence.
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Raghunathan SB, Schouten HF, Visser TD. Topological reactions of correlation functions in partially coherent electromagnetic beams. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2013; 30:582-588. [PMID: 23595316 DOI: 10.1364/josaa.30.000582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
It was recently shown that so-called coherence vortices, singularities of the two-point correlation function, generally occur in partially coherent electromagnetic beams. We study the three-dimensional structure of these singularities and show that in successive cross sections of a beam a rich variety of topological reactions takes place. These reactions involve, apart from vortices, the creation or annihilation of dipoles, saddles, maxima and minima of the phase of the correlation function. Since these reactions happen generically, i.e., under quite general conditions, these observations have implications for interference experiments with partially coherent, electromagnetic beams.
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Affiliation(s)
- Shreyas B Raghunathan
- Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, The Netherlands
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