Metasurfaces, composed of sub-wavelength structures, have a powerful capability to manipulate light propagations. However, metasurfaces usually work either in pure reflection mode or pure transmission mode. Achieving full-space manipulation of light at will in the optical region is still challenging. Here we propose a design method of full-space meta-device containing a bilayer metasurface sandwiching 1D photonic crystal to manipulate the transmitted and reflected wave independently. To provide a proof-of-concept demonstration, a device is proposed to show the light focusing in transmission and a vortex beam in reflection. Meanwhile, a device focusing the reflected light with oblique 45° incidence and the transmitted light with normal incidence is designed to indicate its application potential in augmented reality (AR) application. Our design provides a promising way to enrich the multifunctional meta-devices for potential applications.
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http://dx.doi.org/10.1364/OL.501949 | DOI Listing |
Sci Rep
January 2025
School of Electronic Science and Engineering, Xiamen University, Xiamen, 361005, China.
Metasurfaces have exhibited excellent capabilities in controlling main characteristics of electromagnetic fields. Thus, a lot of significant achievements have been attained in many areas especially in the fields of hologram and near-field imaging. However, some of these designs are implemented in a manner of interleaved subarrays that complicates the design and makes them difficult to achieve integration.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
Flat bands have empowered novel phenomena such as robust canalization with strong localization, high-collimation and low-loss propagation. However, the spatial symmetry protection in photonic or acoustic lattices naturally forces flat bands to manifest in pairs aligned at an inherently specific angle, resulting in a fixed bidirectional canalization. Here, we report an acoustic flat-band metasurface, allowing not only unidirectional canalization at all in-plane angles but also robust tunability in band alignment.
View Article and Find Full Text PDFSci Rep
January 2025
School of Electronic Science and Engineering, Xiamen University, Xiamen, 361005, China.
Vanadium dioxide (VO) exhibits exceptional phase transition characteristics that enable dynamic manipulation of electromagnetic wave. In this study, a novel design of bilayer isotropic metasurface is introduced. It leverages insulating-to-metallic phase transition of VO to enable broadband holography for terahertz wave.
View Article and Find Full Text PDFNanophotonics
November 2024
Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, 27695, USA.
Diffractive Neural Networks (DNNs) leverage the power of light to enhance computational performance in machine learning, offering a pathway to high-speed, low-energy, and large-scale neural information processing. However, most existing DNN architectures are optimized for single tasks and thus lack the flexibility required for the simultaneous execution of multiple tasks within a unified artificial intelligence platform. In this work, we utilize the polarization and wavelength degrees of freedom of light to achieve optical multi-task identification using the MNIST, FMNIST, and KMNIST datasets.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Institute of High-Performance Computing, Agency for Science, Technology, and Research (A-STAR), Fusionopolis, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore.
In this study, we construct Fabry-Perot cavities in which nanostructured, thin resonant metasurfaces act as mirrors. We develop a temporal coupled-mode theory and provide an accurate description of the resonances supported by these cavities, deriving analytically their transmission characteristics. The presence of metasurface mirrors introduces a substantial group delay, causing the field concentration to shift from the bulk of the cavity towards the regions close to the two metasurfaces.
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