A novel, polarization insensitive, wide-angle and broadband electromagnetic metamaterial absorber, which can cover either a flat or a bent geometry, is presented in this work. The periodic geometry has a unit-cell, which consists of four split ring resonators, which are sequentially rotated around the unit-cell axis progressively by 90 deg. First, the metallic parts of the geometry consists of low resistivity copper traces. Next, in order to increase the frequency bandwidth, resistively loaded traces, printed by conventional inkjet printer are used to replace the copper ones. For normal incidence, simulated and measurement results shown that the proposed flat absorber exhibits absorption efficiency higher than 0.8 for 6.9-29.9 GHz (i.e., bandwidth of 125%) regardless of polarization, while the curved absorber for 6.6-29 GHz (i.e., bandwidth of 126%) or for 10.5-29.6 GHz (i.e., bandwidth of 95%), depending the polarization. For oblique incidence and for TE or TM polarized incident wave it presents bandwidth of 118% (7.7-29.9 GHz) or 100.5% (9.9-29.9 GHz), respectively, for an incident angular range of 0-45 deg. Finally, the proposed absorber has thickness of 3.89 mm, corresponding to λ/11.7 at its lowest operation frequency.
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http://dx.doi.org/10.1038/s41598-019-48761-6 | DOI Listing |
We propose and experimentally demonstrate liquid crystal-based computer-generated image holography enabled by the Pancharatnam-Berry phase modulation. Such a device exhibits distinctive properties, such as natural light illumination, polarization insensitivity, broadband optical response, high polarization conversion efficiency, and direct visibility to the naked eye. These unique attributes make this type of image holography a promising avenue for applications in optical information storage, anti-counterfeiting, and advanced information displays.
View Article and Find Full Text PDFIn this paper, we propose and demonstrate an integrated polarization-insensitive single-mode filter (SMF) on a 340 nm silicon-on-insulator (SOI) platform, by introducing two lateral coupling waveguides to couple high-order modes from central single-mode waveguide to lateral waveguides. The experimental results show that the excess loss is <0.29 dB and the extinction ratio is >20 dB with a broad bandwidth of 136 nm for the fabricated SMF with a compact footprint of <13 µm.
View Article and Find Full Text PDFAdv Mater
January 2025
Laboratory of Advanced Materials, Institute of Optoelectronics, Fudan University, Shanghai, 200438, P. R. China.
Metal single atoms (SA)-support interactions inherently exhibit significant electrochemical activity, demonstrating potential in energy catalysis. However, leveraging these interactions to modulate electronic properties and extend application fields is a formidable challenge, demanding in-depth understanding and quantitative control of atomic-scale interactions. Herein, in situ, off-axis electron holography technique is utilized to directly visualize the interactions between SAs and the graphene surface.
View Article and Find Full Text PDFRev Sci Instrum
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OFS Laboratories, 19 Schoolhouse Road, Somerset, New Jersey 08873, USA.
Transmission matrix measurements of multimode fibers are now routinely performed in numerous laboratories, enabling control of the electric field at the distal end of the fiber and paving the way for the potential application to ultrathin medical endoscopes with high resolution. The same concepts are applicable to other areas, such as space division multiplexing, targeted power delivery, fiber laser performance, and the general study of the mode coupling properties of the fiber. However, the process of building an experimental setup and developing the supporting code to measure the fiber's transmission matrix remains challenging and time consuming, with full details on experimental design, data collection, and supporting algorithms spread over multiple papers or lacking in detail.
View Article and Find Full Text PDFNanoscale
December 2024
National Key Laboratory of Advanced Micro and Nano Fabrication Technology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Broadband metamaterial absorbers in the long wavelength infrared region are promising in applications including thermal imaging, cloaking, radiative cooling and IR signature suppression. Although high absorption over the long wavelength infrared region has been extensively achieved, the challenge is to shrink both the thickness and lateral footprint of unit absorbing structures. Here, a compact broadband long wavelength infrared metamaterial absorber consisting of multilayered Ge/Ti/Ge/SiO hybrid cylindrical structures, whose period and thickness are only ∼1.
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