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Author

Qiwen Zhan

Bio: Qiwen Zhan is an academic researcher from University of Shanghai for Science and Technology. The author has contributed to research in topics: Polarization (waves) & Fiber laser. The author has an hindex of 40, co-authored 336 publications receiving 9107 citations. Previous affiliations of Qiwen Zhan include Quanzhou Normal University & Wright-Patterson Air Force Base.


Papers
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Journal ArticleDOI
Qiwen Zhan1
TL;DR: An overview of the recent developments in the field of cylindrical vector beams is provided in this paper, where the authors also discuss the potential of using these beams in other fields.
Abstract: An overview of the recent developments in the field of cylindrical vector beams is provided. As one class of spatially variant polarization, cylindrical vector beams are the axially symmetric beam solution to the full vector electromagnetic wave equation. These beams can be generated via different active and passive methods. Techniques for manipulating these beams while maintaining the polarization symmetry have also been developed. Their special polarization symmetry gives rise to unique high-numerical-aperture focusing properties that find important applications in nanoscale optical imaging and manipulation. The prospects for cylindrical vector beams and their applications in other fields are also briefly discussed.

2,361 citations

Journal ArticleDOI
Qiwen Zhan1
TL;DR: Numerical studies show that optical tweezers using radial polarization can stably trap metallic particles in 3-dimension due to the spatial separation of the gradient force and scattering/absorption forces.
Abstract: Metallic particles are generally considered difficult to trap due to strong scattering and absorption forces. In this paper, numerical studies show that optical tweezers using radial polarization can stably trap metallic particles in 3-dimension. The extremely strong axial component of a highly focused radially polarized beam provides a large gradient force. Meanwhile, this strong axial field component does not contribute to the Poynting vector along the optical axis. Consequently, it does not create axial scattering/absorption forces. Owing to the spatial separation of the gradient force and scattering/absorption forces, a stable 3-D optical trap for metallic particles can be formed.

747 citations

Journal ArticleDOI
TL;DR: A focus shaping technique using generalized cylindrical vector beams that can be tailored by appropriately adjusting the rotation angle to obtain peak-centered, donut and flattop focal shapes is reported.
Abstract: We report a focus shaping technique using generalized cylindrical vector beams. A generalized cylindrical vector beam can be decomposed into radially polarized and azimuthally polarized components. Such a generalized cylindrical beam can be generated from a radially polarized or an azimuthally polarized light using a two-half-wave-plate polarization rotator. The intensity pattern at the focus can be tailored by appropriately adjusting the rotation angle. Peak-centered, donut and flattop focal shapes can be obtained using this technique.

572 citations

Journal ArticleDOI
TL;DR: The experimental confirmation of the focusing properties and field enhancement effect of plasmonic lens made of multiple concentric annular rings using a collection mode near field scanning optical microscope.
Abstract: Optimal plasmonic focusing can be achieved through matching the rotational symmetry of the plasmonic lens to the polarization symmetry of a radially polarized illumination. In this letter, we report the experimental confirmation of the focusing properties and field enhancement effect of plasmonic lens made of multiple concentric annular rings using a collection mode near field scanning optical microscope. Surface plasmons excited at all azimuthal directions propagate toward the geometric center and constructively interfere at the focus to create a strongly enhanced evanescent optical “needle” field that is substantially polarized vertically to the plasmonic lens surface. The field enhancement factor can be improved through adding more rings while maintaining the plasmonic focal spot size. Strategy for optimizing the field enhancement factor is studied with both analytical and numerical methods.

258 citations

Journal ArticleDOI
TL;DR: The existence of the vectorial vortex can be identified with longer propagation distance than the scalar vortex even with vanishing characteristic vortex structure in the irradiance images, indicating the potential advantages of using a vector vortex beam to mitigate atmospheric effects and enable a more robust free space communication channel with longer link distance.
Abstract: We numerically study the propagation properties of vector vortex beams through a turbulent atmosphere. The irradiance pattern, degree of polarization, and scintillation index of radially polarized beam are computed for different propagation distances in an atmosphere with weak and strong turbulences. Corresponding properties of a fundamental Gaussian beam and a scalar vortex beam with topological charge of + 1 propagating through the same atmospheric turbulence conditions are calculated for comparison. With the same initial intensity profile, the vector vortex beam shows substantially lower scintillation than the scalar vortex. The existence of the vectorial vortex can be identified with longer propagation distance than the scalar vortex even with vanishing characteristic vortex structure in the irradiance images. This indicates the potential advantages of using a vector vortex beam to mitigate atmospheric effects and enable a more robust free space communication channel with longer link distance.

222 citations


Cited by
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Journal ArticleDOI
Qiwen Zhan1
TL;DR: An overview of the recent developments in the field of cylindrical vector beams is provided in this paper, where the authors also discuss the potential of using these beams in other fields.
Abstract: An overview of the recent developments in the field of cylindrical vector beams is provided. As one class of spatially variant polarization, cylindrical vector beams are the axially symmetric beam solution to the full vector electromagnetic wave equation. These beams can be generated via different active and passive methods. Techniques for manipulating these beams while maintaining the polarization symmetry have also been developed. Their special polarization symmetry gives rise to unique high-numerical-aperture focusing properties that find important applications in nanoscale optical imaging and manipulation. The prospects for cylindrical vector beams and their applications in other fields are also briefly discussed.

2,361 citations

01 Jan 2016
TL;DR: In this paper, the authors present the principles of optics electromagnetic theory of propagation interference and diffraction of light, which can be used to find a good book with a cup of coffee in the afternoon, instead of facing with some infectious bugs inside their computer.
Abstract: Thank you for reading principles of optics electromagnetic theory of propagation interference and diffraction of light. As you may know, people have search hundreds times for their favorite novels like this principles of optics electromagnetic theory of propagation interference and diffraction of light, but end up in harmful downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some infectious bugs inside their computer.

2,213 citations

Journal ArticleDOI
TL;DR: A metasurface platform based on high-contrast dielectric elliptical nanoposts that provides complete control of polarization and phase with subwavelength spatial resolution and an experimentally measured efficiency ranging from 72% to 97%, depending on the exact design.
Abstract: Metasurfaces are planar structures that locally modify the polarization, phase and amplitude of light in reflection or transmission, thus enabling lithographically patterned flat optical components with functionalities controlled by design. Transmissive metasurfaces are especially important, as most optical systems used in practice operate in transmission. Several types of transmissive metasurface have been realized, but with either low transmission efficiencies or limited control over polarization and phase. Here, we show a metasurface platform based on high-contrast dielectric elliptical nanoposts that provides complete control of polarization and phase with subwavelength spatial resolution and an experimentally measured efficiency ranging from 72% to 97%, depending on the exact design. Such complete control enables the realization of most free-space transmissive optical elements such as lenses, phase plates, wave plates, polarizers, beamsplitters, as well as polarization-switchable phase holograms and arbitrary vector beam generators using the same metamaterial platform.

2,126 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide an overview of the fundamental origins and important applications of the main spin-orbit interaction phenomena in modern optics that play a crucial role at subwavelength scales, including spin-Hall effects in inhomogeneous media and at optical interfaces, spindependent effects in non-paraxial (focused or scattered) fields, spin-controlled shaping of light using anisotropic structured interfaces (metasurfaces).
Abstract: This Review article provides an overview of the fundamental origins and important applications of the main spin–orbit interaction phenomena in modern optics that play a crucial role at subwavelength scales. Light carries both spin and orbital angular momentum. These dynamical properties are determined by the polarization and spatial degrees of freedom of light. Nano-optics, photonics and plasmonics tend to explore subwavelength scales and additional degrees of freedom of structured — that is, spatially inhomogeneous — optical fields. In such fields, spin and orbital properties become strongly coupled with each other. In this Review we cover the fundamental origins and important applications of the main spin–orbit interaction phenomena in optics. These include: spin-Hall effects in inhomogeneous media and at optical interfaces, spin-dependent effects in nonparaxial (focused or scattered) fields, spin-controlled shaping of light using anisotropic structured interfaces (metasurfaces) and robust spin-directional coupling via evanescent near fields. We show that spin–orbit interactions are inherent in all basic optical processes, and that they play a crucial role in modern optics.

1,642 citations

Journal ArticleDOI
TL;DR: Bound states in the continuum (BICs) are waves that remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away.
Abstract: Bound states in the continuum (BICs) are waves that remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away. Their very existence defies conventional wisdom. Although BICs were first proposed in quantum mechanics, they are a general wave phenomenon and have since been identified in electromagnetic waves, acoustic waves in air, water waves and elastic waves in solids. These states have been studied in a wide range of material systems, such as piezoelectric materials, dielectric photonic crystals, optical waveguides and fibres, quantum dots, graphene and topological insulators. In this Review, we describe recent developments in this field with an emphasis on the physical mechanisms that lead to BICs across seemingly very different materials and types of waves. We also discuss experimental realizations, existing applications and directions for future work. The fascinating wave phenomenon of ‘bound states in the continuum’ spans different material and wave systems, including electron, electromagnetic and mechanical waves. In this Review, we focus on the common physical mechanisms underlying these bound states, whilst also discussing recent experimental realizations, current applications and future opportunities for research.

1,612 citations