We present a closed-form analytical expression that describes the effect of clipping by circular apertures on laser beams, described in terms of an expansion in eigenmodes of the paraxial wave equation, in either the Laguerre-Gauss or Hermite-Gauss bases. This result provides a faster and more accurate way to compute the coupling between higher-order modes, compared to commonly used grid-based numerical integration.
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http://dx.doi.org/10.1364/JOSAA.448808 | DOI Listing |
Sci Rep
January 2025
Department of Electrical Engineering, Iran University of Science and Technology, Tehran, 16846-1314, Iran.
The holographic technique is one of the simplest methods for designing antennas based on metasurface. This paper presents a spoof surface plasmon polariton (SSPP) leaky-wave antenna (LWA) based on the concept of impedance modulated metasurfaces by the anisotropic holographic technique. Instead of parasitic elements, anisotropic SSPP elements are exploited to achieve radiation with circular polarization.
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December 2024
Institute of Communications Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
A core dielectric cylindrical rod wrapped in a dielectric circular pipe whose outer surface is enclosed by a helical conducting strip grating that is skewed along the axial direction is herein analyzed using the asymptotic strip boundary conditions along with classical vector potential analysis. Targeted for use as a cylindrical holographic antenna, the resultant field solutions facilitate the aperture integration of the equivalent cylindrical surface currents to obtain the radiated far fields. As each rod section of a certain skew angle exhibits a distinct modal attribute; this topology allows for the distribution of the cylindrical surface impedance via the effective refractive index to be modulated, as in gradient-index (GRIN) materials.
View Article and Find Full Text PDFPlant Signal Behav
December 2025
State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu, China.
Abscisic acid (ABA) mediated stomatal closure is a highly effective mode of active stomatal regulation under drought stress. Previous studies on stomatal regulation have primarily focused on the leaves of vascular plants, while research on the stomatal behavior of bulbous plants remains unknown. In addition, ABA-induced stomatal regulation in bulbs has yet to be explored.
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December 2024
Radiating Systems Group, Department of Applied Physics, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
The following paper presents the findings of a study conducted on the distances at which the field generated by a ϕ-symmetric circular Taylor aperture distribution can be classified as far-field, and also the efficiency across various study parameters. The [Formula: see text] transition integers that produce a monotonic distribution, which have been traditionally used and analyzed, are compared with those that yield a peaked distribution, and offer greater efficiency. Additionally, modified circular Taylor [Formula: see text] distributions featuring synthesized patterns with one or two depressed inner sidelobes, which have not been previously explored, are also examined.
View Article and Find Full Text PDFNanophotonics
September 2024
Air and Missile Defense College, Air Force Engineering University, Xi'an 710051, China.
Achieving independent multitasked wavefront control by using an ultrathin plate is a challenge to increase information capacity in integration optics and radar applications. Transmission-reflection-integrated metasurface provides an efficient recipe primarily for multifunctional meta-device, however it is challenging to synergize both linear polarization (LP) and circular polarization (CP) using a single meta-plate. Here, a multichannel full-space coding metasurface composed of interleaved shared-aperture meta-atom is proposed to achieve large information capacity by capsulating judiciously engineered high efficiency triple sub-elements (modes) in four-layer scheme.
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