Observation of photonic spin Hall effect (SHE) in dielectric metasurfaces whose local optical axes are spatially rotated is presented. The photonic SHE manifests itself as a spin-dependent splitting in momentum space due to the space-variant Pancharatnam-Berry phase. We show that no spin-dependent splitting occurs when keeping the rotational symmetry of local optical axes. However, the splitting can be observed when the rotational symmetry is broken. The spin-dependent splitting in position space can be observed in the far field due to the high transmission efficiency of dielectric metasurfaces. Moreover, it can be enhanced by increasing the rotation rate of local optical axes in the metasurfaces.
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http://dx.doi.org/10.1364/OL.40.000756 | DOI Listing |
Nano Lett
January 2025
Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States.
Metasurfaces supporting narrowband resonances are of significant interest in photonics for molecular sensing, quantum light source engineering, and nonlinear photonics. However, many device architectures rely on large refractive index dielectric materials and lengthy fabrication processes. In this work, we demonstrate quasi-bound states in the continuum (quasi-BICs) using a polymer metasurface exhibiting experimental quality factors of 305 at visible wavelengths.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité and CNRS, Paris, 75013, France.
Vortex beams are currently drawing a great deal of interest, from fundamental research to several promising applications. While their generation in bulky optical devices limits their use in integrated complex systems, metasurfaces have recently proven successful in creating optical vortices, especially in the linear regime. In the nonlinear domain, of strategic importance for the future of classical and quantum information, to date orbital angular momentum has only been created in qualitative ways, without discussing discrepancies between design and experimental results.
View Article and Find Full Text PDFIn this work, a specially designed multilayer indium tin oxide (ITO) mesh structure metasurface was proposed as a microwave absorber, achieving both excellent angle-insensitive broadband absorption and high shielding effectiveness (SE). It features gradually changing surface resistance ( ), to expand the absorption bandwidth while maintaining high SE. Also, a folded square ring metasurface was designed to effectively suppress surface wave grating lobes, as well as to reduce the unit size of the metasurface and thus the absorber.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong, 999077, China.
Optical edge detection is a crucial optical analog computing method in fundamental artificial intelligence, machine vision, and image recognition, owing to its advantages of parallel processing, high computing speed, and low energy consumption. Field-of-view-tunable edge detection is particularly significant for detecting a broader range of objects, enhancing both practicality and flexibility. In this work, a novel approach-adaptive optical spatial differentiation is proposed for field-of-view-tunable edge detection.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Research Center of Applied Electromagnetics, Nanjing University of Information Science and Technology, Nanjing 210044, China.
We present a novel photoreconfigurable metasurface designed for independent and efficient control of electromagnetic waves with identical incident polarization and frequency across the entire spatial domain. The proposed metasurface features a three-layer architecture: a top layer incorporating a gold circular split ring resonator (CSRR) filled with perovskite material and dual -shaped perovskite resonators; a middle layer of polyimide dielectric; and a bottom layer comprising a perovskite substrate with an oppositely oriented circular split ring resonator filled with gold. By modulating the intensity of a laser beam, we achieve autonomous manipulation of incident circularly polarized terahertz waves in both transmission and reflection modes.
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