We proposed an ingenious, highly efficient TiO meta-atom (MA)-based near-infrared disordered metalens structure harnessing bird's eye-inspired hyperuniform distribution and analyzed its optical and imaging properties employing the finite-difference time-domain (FDTD) method. The hyperuniform disordered MAs constructed an image at a focal length by engineering the phase shift of transmittance. We obtained a high focusing efficiency of 84.39% at a wavelength of 820 nm for disordered metalens structures. Amazingly, our proposed disordered metalens structures can mimic the optical properties of ordered metalens structures. Similar focusing efficiencies of disordered and ordered metalens structures were found in a wavelength range from 850 to 890 nm due to the long-range periodic properties of hyperuniform disordered structures. The focal length shifts and NAs of disordered metalens structures were comparable to the focal length shifts and NAs of periodic metalens structures in the entire operating region from 770 to 970 nm with a constant FWHM of 1.503 μm. Our proposed structure paves the way for designing new and innovative imaging, sensing, and spectroscopic technologies, such as lidar, medical devices, IR and machine vision cameras, display systems, and holography.
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http://dx.doi.org/10.1039/d4na00661e | DOI Listing |
Nanoscale Adv
December 2024
Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology Dhaka Bangladesh
Light Sci Appl
January 2025
Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtzplatz 1, Eggenstein-Leopoldshafen, 76344, Germany.
The core advantage of metalenses over traditional bulky lenses lies in their thin volume and lightweight. Nevertheless, as the application scenarios of metalenses extend to the macro-scale optical imaging field, a contradiction arises between the increasing demand for large-aperture metalenses and the synchronous rise in design and processing costs. In response to the application requirements of metalens with diameter reaching the order of 10λ or even 10λ, this paper proposes a novel design method for fixed-height concentric-ring metalenses, wherein, under the constraints of the processing technology, a subwavelength 2D building unit library is constructed based on different topological structures, and the overall cross-section of the metalens is assembled.
View Article and Find Full Text PDFNanophotonics
September 2024
National Mobile Communications Research Laboratory, School of Information Science and Engineering, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing 210096, China.
Due to signal shielding caused by building structures, conventional mature positioning technologies such as the Global Positioning System (GPS) are only suitable for outdoor navigation and detection. However, there are many scenarios that urgently require high-precision indoor positioning technologies, such as indoor wireless optical communications (OWCs), navigation in large buildings, and warehouse management. Here, we proposed a millimeter-precision indoor positioning technology based on metalens-integrated camera, which determines the position of the device through imaging of beacon LEDs.
View Article and Find Full Text PDFThe achievement of distinct wavefront reconstruction for orthogonally polarized electromagnetic (EM) waves in a broadband frequency range is extremely important in modern wireless communications. However, the development of circularly polarized wavefront modulation devices is hindered by conjugate symmetric phase responses introduced by the rotation-induced geometric phase. Herein, a spin-decoupled meta-atom with a novel structure is designed to independently tailor left-hand and right-hand circularly polarized incident waves over a broadband range of 12-28 GHz with a fractional bandwidth of 80%.
View Article and Find Full Text PDFAdv Sci (Weinh)
November 2024
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Instrumentation, University of Science and Technology of China, Hefei, 230026, China.
Infrared (IR) radiation thermography is extensively utilized in diverse fields due to its non-contact capability. Nevertheless, its effectiveness is often compromised by the significant emissivity variations among different objects, limiting its application to specific setups or focused object types. Colorimetric thermography is introduced as an alternative emissivity-independent method of radiation thermometry.
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