Broadband asymmetric transmission characteristics based on metamaterial in terahertz region

Zheng, Xiaoliang; Guoqiang, Shang; Zhao, Dongjie; Yang, Baoping; Wang, Xiaomin; Fan, Jinqiang; Ren, Siheng

doi:10.1088/1742-6596/1649/1/012049

Cited by 2 publications

(3 citation statements)

References 16 publications

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“…Accordingly, the numerical results demonstrate that the proposed metasurface provides the absolute values of the asymmetric transmission coefficients greater than 0.9 within the 0.52-1.10 THz frequency band and the polarization conversion rates greater than 99% in the 0.10-1.69 THz frequency band. Compared with the results of [41,47,[68][69][70], the performance of the metasurface structure in this research is near perfect. This confirms that the optimized design is effective.…”

Section: Performance Of the Metasurface With Central Gold Layersmentioning

confidence: 63%

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Chiral metasurface design with highly efficient and controllable asymmetric transmission and perfect polarization conversion of linearly polarized electromagnetic waves in the THz range

Luo¹,

Qiu²,

Moumni³

et al. 2022

J. Phys. D: Appl. Phys.

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The influences of metasurfaces on the propagation of electromagnetic waves generate several important effects, such as asymmetric transmission and polarization conversion, that are highly useful in optical and microwave communication applications. However, easy method for dynamically controlling the asymmetric transmission of linearly polarized waves with perfect polarization conversion and high efficiency over a wide band in the THz range remain poorly developed. Our work addresses this issue by designing a novel metasurface structure consisting of two outer orthogonal gratings and a central lattice with an optimized chiral graphene monolayer distribution topology sandwiched between dielectric substrates. The frequency-dependent performance of the proposed metasurface is evaluated according to analyses of the asymmetric transmission coefficient, polarization conversion rate, total transmission coefficient, polarization rotation angle, ellipticity, and chirality parameter based on the results of simulations. The results demonstrate that the proposed structure provides highly efficient asymmetric transmission of linearly polarized waves and perfect polarization conversion in the high frequency range from 0.1 to 3.0 THz. The asymmetric transmission and the polarization conversion of the structure are dynamically controllable by changing the Fermi energy of graphene from 0 eV to 1 eV. The results of the analysis reveal that the observed dynamic controllability is a function of the interrelation between the special configuration of the chiral metasurface structure and the special properties of graphene.

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Section: Performance Of the Metasurface With Central Gold Layersmentioning

confidence: 63%

“…The metallic gold is dealt with using the Drude model. That is, the effective permittivity of the metals in the terahertz spectral region is given by [68]:…”

Section: Optimized Chiral Metasurfacementioning

confidence: 99%

Chiral metasurface design with highly efficient and controllable asymmetric transmission and perfect polarization conversion of linearly polarized electromagnetic waves in the THz range

Luo¹,

Qiu²,

Moumni³

et al. 2022

J. Phys. D: Appl. Phys.

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“…1. Diagram of THz spectroscopy system adopted from Fischer [9] Investigating the potential of THz spectroscopy to identify neurodegenerative illnesses in human brains is an intriguing topic due to the inherent capacity of THz rays to non-invasively permeate practically all materials [10]. Since amyloid fibrils are cylindrical and are known to scatter light in the THz spectral range, our findings suggest a non-invasive method to identify amyloid disorders in humans [11].…”

Section: Introductionmentioning

confidence: 90%

Terahertz Spectroscopy Analysis of Amyloid Fibrils Derived from Human Serum Albumin

Shakirah Wahida Shamsul Bahri,

Siti Nor Khadijah Addis,

Nur Farizan Munajat

et al. 2024

ARASET

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Amyloid fibrils, also referred to as protein fibrils, represent irregular assemblies of proteins exhibiting a cross-β configuration. Terahertz radiation, a segment of the electromagnetic spectrum spanning 0.3 to 10 terahertz (THz), is known to interact with these fibrils due to their cylindrical shape. This study's objective was to explore the potential of terahertz spectroscopy as a non-invasive means to detect the progressive growth of protein fibrils. In this investigation, human serum albumin (HSA) was synthetically induced to form protein fibrils. Confirmation of fibril formation was done by fluorescence spectroscopy, Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectroscopy, and Terahertz time-domain spectroscopy (THz-TDS). To initiate the process, HSA was dissolved in distilled water at a concentration of 160 µM, followed by the addition of 60% ethanol to both samples for dilution. The HSA to Cu (II) ratio was maintained at 1:1 (160 µM) for stock solutions containing Cu (II). Subsequently, each set underwent a 6-hour heating phase at 65 °C to cultivate fibrils, which were then stored at room temperature for 30, 60, and 90 days before evaluation. Incubation of human serum albumin yielded amyloid fibrils as evidenced by ThT fluorescence, FT-IR spectroscopy revealed an emergence of fibrils within the amide I bands, extending from 1630 cm⁻¹ to 1650 cm⁻¹ and UV-Vis spectroscopy disclosed the augmentation of protein fibril absorbance over the incubation period. THz spectroscopy absorbance progressively heightened with prolonged heating of the protein fibrils due to the hydration shell surrounding them. Through these spectroscopic methods, it was elucidated that the fibrillation process led to the gradual development of β-sheet and unordered helix structures as well as the potential of THz spectroscopy as non-invasive tool for detection and monitoring of amyloidal diseases, promising insights into early diagnosis and treatment strategies.

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Broadband asymmetric transmission characteristics based on metamaterial in terahertz region

Cited by 2 publications

References 16 publications

Chiral metasurface design with highly efficient and controllable asymmetric transmission and perfect polarization conversion of linearly polarized electromagnetic waves in the THz range

Chiral metasurface design with highly efficient and controllable asymmetric transmission and perfect polarization conversion of linearly polarized electromagnetic waves in the THz range

Terahertz Spectroscopy Analysis of Amyloid Fibrils Derived from Human Serum Albumin

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