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Tiegen Liu - One of the best experts on this subject based on the ideXlab platform.

  • Polarimetric underwater image recovery based on circularly polarized illumination and histogram stretching
    AOPC 2019: Optical Sensing and Imaging Technology, 2019
    Co-Authors: Hui Wang, Tiegen Liu
    Abstract:

    Due to the backscattered Light and signal attenuation, the underwater imaging could be severely degraded by the scattering media, especially in the case of strong scattering for dense turbid medium. Considering the circular Polarization Light can persist better its Polarization property during propagating through turbid media compared with the linear Polarization Light. In this paper, we two polarimetric recovery methods based on the circularly polarized illumination. The first one is based on the combination of both linearly and circularly Polarization information. The second one is an improved method for recovering the underwater image by combining histogram analysis. The real-world experiments shown that, by using circularly polarized illumination, the traditional polarimetric dehazing method is optimized which is suitable for use in the strong scattering environment, especially when the method is combined with histogram stretching.

  • Polarimetric image recovery in turbid media employing circularly polarized Light.
    Optics express, 2018
    Co-Authors: Lin Zhao, Hui Wang, Jingyu Yang, Tiegen Liu
    Abstract:

    Circular Polarization memory is a well-known phenomenon indicating that the circular Polarization Light can persist better its Polarization property during propagating through turbid media compared with the linear Polarization Light. Therefore, in principle, using circularly polarized Light can probably improve the quality of image recovery in dense turbid media than using the linearly polarized Light. In this paper, we propose a new polarimetric image recovery method in dense turbid media with the illumination Light of circular Polarization, and we realize the image recovery combining the circular Polarization information and linearly Polarization information. The real-world experiment results demonstrate that the proposed method is more effective than previous methods, including the traditional polarimetric image recovery method by Schechner’s [Appl. Opt.42, 511 (2003)] based on linear Polarization.

Hongwen Ren - One of the best experts on this subject based on the ideXlab platform.

  • Polarization converting textures of nematic liquid crystal in glass cavities
    Journal of Applied Physics, 2014
    Co-Authors: Xiahui Wang, Hongwen Ren
    Abstract:

    When a nematic liquid crystal (LC) is filled in a glass cavity, the LC molecules present azimuthal orientations in the cavity. If the surface of the cavity is coated with a homeotropic polyimide, then the LC molecules exhibit radial orientations. By treating the LC on one side of the cavity with homogeneous alignment, the former orientations change to a twisted-azimuthal texture, while the latter orientations change to a twisted-radial texture. Both textures are verified experimentally, and they can convert a linearly Polarization Light to an azimuthal and/or radial Polarization Light, depending on the Polarization direction of the incident Light. In contrast to previous approaches, various LC textures can be easily formed in a cavity, and the fabrication procedure is simple. Since the LC texture is confined in a cavity, an array pattern of the texture can be obtained, if the employed substrate has multiple cavities. A LC with twisted-azimuthal and/or twisted-radial textures in a cavity array has potential applications in phase modulation, Polarization compensating, sharp focus, and material processing.

  • A Polarization converter array using a twisted-azimuthal liquid crystal in cylindrical polymer cavities
    Optics express, 2013
    Co-Authors: Xiahui Wang, Hongwen Ren, Qiong-hua Wang
    Abstract:

    We report a simple method to prepare an array of Polarization converters using a twisted-azimuthal nematic liquid crystal (NLC) in cylindrical polymer cavities. When a NLC is filled in a cylindrical polymer cavity, LC in the cavity presents concentrically circular orientations. By treating LC on one side of the cavity with homogeneous alignment, a twisted-azimuthal texture is formed. Such a LC texture can convert a linear Polarization Light to either radial or azimuthal Polarization Light depending on the Polarization direction of the incident Light. The LC surface on the other side of the cavity is convex, so the Light after passing through the cavity can be focused as well. The LC texture can be fixed firmly using polymer network. In comparison with previous Polarization converters, our Polarization converter has the merits of individually miniature size, array of pattern, and lens character. Our Polarization converter array has potential applications in tight focusing, imaging, and material processing.

  • Liquid Crystal Polarization Converters Using Circular-Buffed Polystyrene Film
    Japanese Journal of Applied Physics, 2011
    Co-Authors: Kyundo Park, Changwoon Nah, Myong-hoon Lee, Hongwen Ren
    Abstract:

    Polystyrene is well known to align liquid crystal (LC) perpendicular to the rubbing direction. Based on this unique feature, we prepared two cells with special LC alignments using circular-buffed polystyrene as the alignment layer. For the cell with hybrid-radial LC alignment, it can convert a linear Polarization Light to axial Polarization Light; for the cell with twisted-radial LC alignment, it can change a linear Polarization Light into radial Polarization Light. The two LC Polarization cell converters with polystyrene as their alignment layer have the advantages of easy fabrication, simple processing, and scalable size.

Xiahui Wang - One of the best experts on this subject based on the ideXlab platform.

  • Polarization converting textures of nematic liquid crystal in glass cavities
    Journal of Applied Physics, 2014
    Co-Authors: Xiahui Wang, Hongwen Ren
    Abstract:

    When a nematic liquid crystal (LC) is filled in a glass cavity, the LC molecules present azimuthal orientations in the cavity. If the surface of the cavity is coated with a homeotropic polyimide, then the LC molecules exhibit radial orientations. By treating the LC on one side of the cavity with homogeneous alignment, the former orientations change to a twisted-azimuthal texture, while the latter orientations change to a twisted-radial texture. Both textures are verified experimentally, and they can convert a linearly Polarization Light to an azimuthal and/or radial Polarization Light, depending on the Polarization direction of the incident Light. In contrast to previous approaches, various LC textures can be easily formed in a cavity, and the fabrication procedure is simple. Since the LC texture is confined in a cavity, an array pattern of the texture can be obtained, if the employed substrate has multiple cavities. A LC with twisted-azimuthal and/or twisted-radial textures in a cavity array has potential applications in phase modulation, Polarization compensating, sharp focus, and material processing.

  • A Polarization converter array using a twisted-azimuthal liquid crystal in cylindrical polymer cavities
    Optics express, 2013
    Co-Authors: Xiahui Wang, Hongwen Ren, Qiong-hua Wang
    Abstract:

    We report a simple method to prepare an array of Polarization converters using a twisted-azimuthal nematic liquid crystal (NLC) in cylindrical polymer cavities. When a NLC is filled in a cylindrical polymer cavity, LC in the cavity presents concentrically circular orientations. By treating LC on one side of the cavity with homogeneous alignment, a twisted-azimuthal texture is formed. Such a LC texture can convert a linear Polarization Light to either radial or azimuthal Polarization Light depending on the Polarization direction of the incident Light. The LC surface on the other side of the cavity is convex, so the Light after passing through the cavity can be focused as well. The LC texture can be fixed firmly using polymer network. In comparison with previous Polarization converters, our Polarization converter has the merits of individually miniature size, array of pattern, and lens character. Our Polarization converter array has potential applications in tight focusing, imaging, and material processing.

Lin Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Polarimetric image recovery in turbid media employing circularly polarized Light.
    Optics express, 2018
    Co-Authors: Lin Zhao, Hui Wang, Jingyu Yang, Tiegen Liu
    Abstract:

    Circular Polarization memory is a well-known phenomenon indicating that the circular Polarization Light can persist better its Polarization property during propagating through turbid media compared with the linear Polarization Light. Therefore, in principle, using circularly polarized Light can probably improve the quality of image recovery in dense turbid media than using the linearly polarized Light. In this paper, we propose a new polarimetric image recovery method in dense turbid media with the illumination Light of circular Polarization, and we realize the image recovery combining the circular Polarization information and linearly Polarization information. The real-world experiment results demonstrate that the proposed method is more effective than previous methods, including the traditional polarimetric image recovery method by Schechner’s [Appl. Opt.42, 511 (2003)] based on linear Polarization.

Kun Yang - One of the best experts on this subject based on the ideXlab platform.

  • A Plasmonic based Ultracompact Polarization Beam Splitter on Silicon-on-Insulator Waveguides
    Scientific reports, 2013
    Co-Authors: Qilong Tan, Xuguang Huang, Wen Zhou, Kun Yang
    Abstract:

    An ultracompact Polarization beam splitter (PBS) is designed on silicon-on-insulator (SOI) platform based on the localized surface plasmons (LSPs) excited by particular Polarization Light. The device uses nanoscale silver cylinders as the Polarization selection between two silicon waveguides of a directional coupler. The transverse-magnetic (TM) Polarization Light excites localized surface plasmons and is coupled into the cross port of the directional coupler with a low insert loss, while the transverse-electric (TE) Polarization Light is under restriction. The PBS has a coupling layer with 50 nm width and 1.1 μm length supporting broadband operation. The simulation calculations show that 22.06dB and 23.06dB of extinction ratios for the TE and TM Polarizations were obtained, together with insertion losses of 0.09dB and 0.40dB.