A vector vortex coronagraph (VVC) is one of promising means for imaging extremely faint objects around bright stars such as exoplanets. We present a design of an achromatic VVC, in which an axially-symmetric half-wave plate (AHP) is placed between crossed polarization filters (circular polarizer and analyzer). The circular polarizer and the analyzer are both composed of a polarizer and a quarter-wave plate (QWP). We demonstrate, via Jones calculus and Fourier analysis, that the achromatic stellar elimination can theoretically be realized by optimal polarization filters, even when chromatic AHP and QWPs are used. We carried out laboratory demonstrations of the designed VVC using a photonic-crystal AHP. As a result, we observed achromatic coronagraphic performance, a light suppression level of 7 × 10(-5), over a wavelength from 543 nm to 633 nm.
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http://dx.doi.org/10.1364/OE.21.007400 | DOI Listing |
Sci Rep
January 2025
School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China.
Recently, vortex beams have been widely studied and applied because they carry orbital angular momentum (OAM). It is widely acknowledged in the scientific community that fractional OAM does not typically exhibit stable propagation; notably, the notion of achieving stable propagation with dual-fractional OAM within a single optical vortex has been deemed impracticable. Here, we address the scientific problem through the combined modulation of phase and polarization, resulting in the generation of a dual-fractional OAM vector vortex beam that can stably exist in free space.
View Article and Find Full Text PDFNanophotonics
April 2024
School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China.
The generation of vector beams using metasurfaces is crucial for the manipulation of light fields and has significant application potential, ranging from classical physics to quantum science. This paper introduces a novel dielectric metasurface composed of quarter-wave plate (QWP) meta-atoms, known as a QWP metasurface, designed to generate focused vector beams (VBs) of Bell-like states under right circularly polarized illumination. The propagation phase imparted on both the co- and cross-polarized components of the output field constructs hyperbolic and helical phase profiles with topological charge , whereas the Pancharatnam-Berry (PB) phase acts only on the cross-polarized component to construct another helical phase profile with topological charge .
View Article and Find Full Text PDFIn this study, we propose a novel, to the best of our knowledge, method for designing low-cost, continuously spatially variable polarizers using polarization holography. We use these devices to generate vector vortex beams and detect scalar vortex beams. Our approach begins with designing polarization holograms that act as polarizers, each with distinct transmission axes recorded at various polar angles on polarization-sensitive materials using a dynamic recording system.
View Article and Find Full Text PDFThe vector vortex beams (VVBs) are endowed with helical phase and vector polarization. The rich optical properties of VVBs have attracted extensive concern. Here the geometric phase is applied to manipulate both the phase and polarization of light for switchable generation of VVBs by vortex plates.
View Article and Find Full Text PDFVectorial structured light beams, characterized by their topological charge and non-uniform polarization distribution, are highly promising beam modes for several applications in different domains of optics and photonics. To harness its potential specifically in optical communication, data encryption, and optical trapping, it is necessary to tailor a multitude of these beams with arbitrary and large topological charge and polarization distribution. However, achieving the above-mentioned requires bulky optical setups that necessitate the superposition of two beams or involve complex material fabrication techniques that can directly generate these beams.
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