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Terahertz refractive index sensor based on the guided resonance in a photonic crystal slab
摘要： The optical properties of a photonic crystals slab (PCS) are highly sensitive to environmental variation. PCS thus are an attractive platform for sensing application. We numerically demonstrate a terahertz refractive index sensor based on the guided resonance in a two-dimensional PCS. The PCS consists of a square lattice of air holes in a silicon slab fabricated on a quartz substrate. By varying each structural parameter systematically, we study the dependence of the resonance located around 0.508 THz on the structural parameters of PCS, and then optimize the structural parameters of PCS for a higher sensitivity. We apply the PCS sensor to detect the refractive index of analytes. The sensitivity of the sensor reaches 23.08 GHz/RIU for the resonance located around 0.508 THz. Our results provide insight into the future terahertz spectroscopy for sensing detection.
关键词： Terahertz,Sensor,Photonic crystals,Guided resonance
更新于2025-09-23 15:21:01
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High-Sensitivity Terahertz Refractive Index Sensor in a Multilayered Structure with Graphene
摘要： In this paper, we propose a high‐sensitivity optical sensor at terahertz frequencies based on a composite structure containing a one‐dimensional photonic crystal (1D PC) coated with a layer of monolayer graphene. Between the 1D PC and the graphene there is a sensing medium. This high‐sensitivity phenomenon originates from the excitation of optical resonance between the graphene and the 1D PC. The proposed sensor is highly sensitive to the Fermi energy of graphene, the thickness and refractive index of the sensing medium, and the number of graphene layers. By selecting appropriate parameters, the maximum sensitivity (407.36 / RIU) is obtained. We believe the proposed configuration is promising for fabricating graphene‐based biosensor‐ or gas‐sensor devices and other related applications in the terahertz band.
关键词： optical resonance,terahertz sensor,graphene
更新于2025-09-23 15:19:57
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Tunable localized surface plasmon graphene metasurface for multiband superabsorption and terahertz sensing
摘要： We propose a plasmon induced tunable metasurface for multiband superabsorption and terahertz sensing. It consists of a graphene sheet that facilitates perfect absorption where the graphene pattern at the top layer creates an enhanced evanescent wave that facilitates the metasurface to work as a sensor. The modelling and numerical analysis are carried out using Finite Element Method (FEM) based software, CST microwave studio where a genetic algorithm (GA) is used to optimize the geometric parameters, and metasurface tunability is achieved via an external gate voltage on the graphene. By exploiting graphene’s tunable properties we demonstrate a multiband superabsorption spectra having a maximum absorption of 99.7% in a frequency range of 0.1–2.0 THz that also maintain unique optical performance over a wide incidence angle. Further results show how the superabsorber can be used as a sensor, where the resonance frequency shifts with the refractive index of the surrounding environment.
关键词： Absorber,Graphene,Terahertz Sensor,Metasurface
更新于2025-09-16 10:30:52
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Design of terahertz spectroscopy based optical sensor for chemical detection
摘要： In this article, a new design of circular cladding with a rotated-hexacore in photonic crystal fiber (RH-CPCF) has been suggested for chemical sensing application in the THz regime. The five layers circular cladding and two layers rotated-hexacore in circular shape are designed here. All numerical results are obtained with a procedure of finite element method and perfectly match layered boundary condition in terahertz (THz) wave propagation. After the simulation result, the proposed RH-CPCF shows the high relative sensitivity is 76.44%, 77.16% and 73.20% for three chemicals such as Ethanol (n = 1.354), Benzene (n = 1.366) and Water (n = 1.330) at 1 THz. On the other hand, the low confinement losses are 2.33 × 10?03 dB/m, 3.07 × 10?06 dB/m and 2.84 × 10?02 dB/m for same in three chemicals at 1 THz. Moreover, effective area, effective mode index and total power fraction in core air holes are also briefly described here. In addition, this proposed circular photonic crystal fiber (RH-CPCF) can be used especially for chemical sensing in biomedical, industrial quality control, material research, micro-optics and many communication applications in THz technology.
关键词： Terahertz sensor,Sensitivity,Optical loss profile,Photonic crystal fiber,Optical sensor,FEM based analysis
更新于2025-09-12 10:27:22