Wideband dispersion-free slow light in chirped-slot photonic-crystal coupled waveguides is proposed and theoretically investigated in detail. By systematically analyzing the dependence of band shape on various structure parameters, unique inflection points in the key photonic band with approximate zero group velocity can be obtained in an optimized slot photonic-crystal coupled waveguide. By simply chirping the widths of the photonic-crystal waveguides in the optimized structure, wideband (up to 20 nm) slow-light with optical confinement in the low dielectric slot is demonstrated numerically with relative temporal pulse-width spreading well below 8% as obtained from two-dimensional finite-difference time-domain simulations. The wideband slow-light operation of the proposed structures would offer significant potential for novel compact high-speed optical-signal-processing devices in silicon-based systems.
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http://dx.doi.org/10.1364/OE.18.010567 | DOI Listing |
Sci Rep
January 2025
Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62512, Egypt.
This paper presents a novel investigation of a magnetic sensor that employs Fano/Tamm resonance within the photonic band gap of a one-dimensional crystal structure. The design incorporates a thin layer of gold (Au) alongside a periodic arrangement of Tantalum pentoxide ([Formula: see text]) and Cesium iodide ([Formula: see text]) in the configuration [Formula: see text]. We utilized the transfer matrix method in conjunction with the Drude model to analyze the formation of Fano/Tamm states and the permittivity of the metallic layer, respectively.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
College of Mathematics and Physics, Nanjing Tech University, Nanjing 211816, China.
We propose two types of structures to achieve the control of Fano and electromagnetically induced transparency (EIT) line shapes, in which dual one-dimensional (1D) photonic crystal nanobeam cavities (PCNCs) are side-coupled to a bus waveguide with different gaps. For the proposed type Ⅰ and type Ⅱ systems, the phase differences between the nanobeam periodic structures of the two cavities are and 0, respectively. The whole structures are theoretically analyzed via the coupled mode theory and numerically demonstrated using the three-dimensional finite-difference time-domain (3D FDTD) method.
View Article and Find Full Text PDFNano Lett
January 2025
Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
Monolayer transition metal dichalcogenides are promising materials that not only are atomically thin but also have direct bandgaps, making them highly regarded in optics and optoelectronics. However, their photoluminescence exhibits almost random polarization at room temperature. The emission is also omnidirectional and weak due to the low quantum yield.
View Article and Find Full Text PDFNano Lett
January 2025
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China.
Heliyon
December 2024
Faculty of Electrical and Computer Engineering, Semnan University, Semnan, Iran.
Optical sensors are among the most significant optical devices that have found extensive applications for THz sensing. Surface plasmon-based sensors have attracted increasing attention more than other kinds of optical sensors such as photonic crystal, optical fiber, and graphene sensors, owing to their compact footprint, fast reaction, and high sensitivity value. Therefore, this work reviews plasmonic sensor structures divided into three general categories.
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