We propose a nanostructured hyperbolic metamaterial (HMM) that can make the transition between elliptic and hyperbolic regimes in the near infrared (IR) frequency range. This switchable HMM is a slab made of a periodic stack of metal/Al(2)O(3)/graphene/Al(2)O(3)/metal nano-layers. By tuning the graphene conductivity via tuning its chemical potential, through a variable external bias, the response of this highly anisotropic medium to a monochromatic TM incident light can be switched between a positive/negative refraction regime and a negative refraction/no-transmission regime. The proposed structure is suitable for applications such as beam splitters, modulators, four-port devices, and optical gates.
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http://dx.doi.org/10.1364/AO.54.001206 | DOI Listing |
Nanoscale
January 2025
State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou 510275, China.
Hyperbolic metamaterials (HMMs) have recently attracted significant research attention due to their hyperbolic wavevector iso-frequency contour, which leads to substantial local electric field (EF) enhancements that benefit optical processes, such as the nonlinear generation, quantum science, biomedical sensing, and more. However, three main challenges hinder their practical implementation: the difficulty in exciting their resonant modes using free-space incidence, the weak enhancement of surface EF, and the narrow spectral range of EF enhancements. Herein, we proposed cross-etched HMMs (CeHMMs) as a novel type of HMM, addressing these issues.
View Article and Find Full Text PDFTopological interface states (TISs), known for their distinctive capabilities in manipulating electromagnetic waves, have attracted significant interest. However, in conventional all-dielectric one-dimensional photonic crystal (1DPC) heterostructures, TISs strongly depend on incident angle, which limits their practical applications. Here, we realize an angle-independent TIS in 1DPC heterostructures containing hyperbolic metamaterials (HMMs) for transverse magnetic polarized waves.
View Article and Find Full Text PDFSci Rep
December 2024
Division of Advanced Electrical and Electronics Engineering, Tokyo University of Agriculture and Technology, 2- 24-16 Naka-cho, Koganei-shi, Tokyo, 184-8588, Japan.
A hyperbolic metamaterial absorber has great potential for improving the performance of photo-thermoelectric devices targeting heat sources owing to its broadband absorption. However, optimizing its geometry requires considering numerous parameters to achieve absorption that aligns with the radiation spectrum. Here, we compare three algorithms using deep reinforcement learning for the optimization of a hyperbolic metamaterial absorber.
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 PDFNano Lett
January 2025
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Guangzhou 510632, P. R. China.
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