We investigate optical bound states in the continuum (BICs) supported by a photonic crystal (PhC) slab penetrated with periodic annular holes theoretically. Ultrahigh-quality factor (Q-factor) resonances associated with BICs are obtained with a Q-factor more than 10. The BICs can be seen at nonzero incident angles by tuning the lattice constant, layer thickness, inner pillar radius and the refractive index of the surrounding medium, and figure of merit (FOM) at the BICs can reach infinite theoretically. New Fano resonance line appears with BICs when the annular hole's symmetry is broken, which can be attributed to the change of the waveguide modes and their coupling when the annular hole shape is asymmetrical. We confirm it by tuning the inner pillars' location and size to realize the structure's asymmetry. It is shown the location and size asymmetry of the inner pillars inside each outer hole can impact the reflectivity and the formation of the BICs obviously. Results from finite difference time domain method (FDTD) simulation and temporal coupled mode theory (CMT) calculations agree well, which are beneficial to design elements based on optical BICs in various applications, such as biosensors, perfect filters, and waveguides.
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http://dx.doi.org/10.1038/s41598-018-29930-5 | DOI Listing |
Rev Sci Instrum
December 2024
X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
This paper presents progress made toward the overarching goal to adapt single-photon-counting microcalorimeters to magnetic fusion energy research and demonstrate the value of such measurements for fusion. Microcalorimeter spectrometers combine the best characteristics of x-ray instrumentation currently available on fusion devices: high spectral resolution similar to an x-ray crystal spectrometer and broad spectral coverage sufficient to measure impurity species from Be to W. As a proof-of-principle experiment, a NASA-built x-ray microcalorimeter spectrometer has been installed on the Madison Symmetric Torus (MST) at the Wisconsin Plasma Physics Laboratory.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Electronics, Carleton University, Ottawa, ON, K1S 5B6, Canada.
In this paper, we propose a novel structure of anisotropic graphene-based hyperbolic metamaterial (AGHMM) sandwiched as a defect between two one-dimensional photonic crystals (PCs) in the terahertz (THz) region. The proposed structure is numerically simulated and analyzed using the transfer matrix method, effective medium theory and three-dimensional finite-difference time-domain. The defect layer of AGHMM consists of graphene sheets separated by subwavelength dielectric spacers.
View Article and Find Full Text PDFTalanta
December 2024
Institute of Biomedical Precision Testing and Instrumentation, College of Artificial Intelligence, Taiyuan University of Technology, Taiyuan, Shanxi, 030600, PR China.
Developing a fluorescence sensing platform for point-of-care detection of low abundance biomarkers is highly valuable for early diagnosis of disease. Herein, a biomimetic fluorescence-enhanced platform based on photonic crystals and DNAzyme walker was constructed and further applied to visualize and quantify the miRNA-21 in biological samples. The DNAzyme walker was orthogonally activated by the target miRNA-21, which enabled the unlocking of the DNAzyme walker strand and the subsequently repeated substrate cleavage, thus generating enhanced fluorescence signals.
View Article and Find Full Text PDFFood Chem
December 2024
Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 300070 Tianjin, People's Republic of China; Tianjin Key Laboratory of Environment, Nutrition and Public Health, Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin Medical University, Tianjin, People's Republic of China. Electronic address:
A novel biomimetic molecular imprinted polymer chip with fluorescence (FL) and structural (STR) states, inspired by color patterns of chameleon skin, is fabricated for detecting diethylstilbestrol (DES). The chip features a regularly structured, non-closed-packed (NCP) colloidal photonic crystal (CPC) lattice made monodisperse MIP spheres containing fluorescence poly ionic liquid (FPIL) pigments. The FL color originates from FPIL pigments and is further enhanced by the Purcell effect, while the STR color results from the periodic arrangement of the NCP CPC structure.
View Article and Find Full Text PDFNanomicro Lett
December 2024
Department of Chemistry and Laboratory of Advanced Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Chemistry for Energy Materials (2011-iChEM), College of Chemistry and Materials, Fudan University, Shanghai, People's Republic of China.
Chloroform and other volatile organic pollutants have garnered widespread attention from the public and researchers, because of their potential harm to the respiratory system, nervous system, skin, and eyes. However, research on chloroform vapor sensing is still in its early stages, primarily due to the lack of specific recognition motif. Here we report a mesoporous photonic crystal sensor incorporating carbon dots-based nanoreceptor (HMSS@CDs-PCs) for enhanced chloroform sensing.
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