Investigation on the tunable and polarization sensitive three-band terahertz graphene metamaterial absorber

Zhan, Ying; Fan, Cunyuan

doi:10.1088/2053-1591/acd61d

Cited by 5 publications

(4 citation statements)

References 56 publications

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“…The unique tunable properties of graphene can be achieved by applying a bias voltage to change its Fermi level, which can affect the carrier concentration and achieve dynamic tunability of the sensor. The relationship between the Fermi level μ c and the bias voltage V g can be described as follows [ 32 ]:

where

is the capacitance of the structural model,

is the vacuum intermediate constant,

is the dielectric constant, and d is the thickness of the middle dielectric layer. As shown in Figure 7 , the structure parameters are set as L 1 = 7 μm, L 2 = 3.7μm, d 1 = 1 μm, and d 2 = 1.5 μm; when the Fermi level (μ c ) increases from 0.4 eV to 0.8 eV, both of the dual-frequency absorption peaks give remarkably blue shift and bandwidth widening.…”

Section: Resultsmentioning

confidence: 99%

Graphene-Based Tunable Dual-Frequency Terahertz Sensor

Fu,

Ye,

Niu

et al. 2024

Nanomaterials

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A tunable dual-band terahertz sensor based on graphene is proposed. The sensor consists of a metal bottom layer, a middle dielectric layer, and single-layer graphene patterned with four strips on the top. The numerical simulations results show that the proposed sensor exhibits two significant absorption peaks at 2.58 THz and 6.07 THz. The corresponding absorption rates are as high as nearly 100% and 98%, respectively. The corresponding quality factor (Q) value is 11.8 at 2.58 THz and 29.6 at 6.07 THz. By adjusting the external electric field or chemical doping of graphene, the positions of the dual-frequency resonance peak can be dynamically tuned. The excitation of plasma resonance in graphene can illustrate the mechanism of the sensor. To verify the practical application of the device, the terahertz response of different kinds and different thicknesses of the analyte is investigated and analyzed. A phenomenon of obvious frequency shifts of the two resonance peaks can be observed. Therefore, the proposed sensor has great potential applications in terahertz fields, such as material characterization, medical diagnosis, and environmental monitoring.

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where

is the capacitance of the structural model,

is the vacuum intermediate constant,

Section: Resultsmentioning

confidence: 99%

Graphene-Based Tunable Dual-Frequency Terahertz Sensor

Fu,

Ye,

Niu

et al. 2024

Nanomaterials

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“…Due to the Pauli exclusion principle, graphene hardly undergoes interband transitions at terahertz frequencies, and the energy loss is very small, which can effectively support the propagation of surface plasmons. The wave vector of graphene's surface plasmon resonance can be expressed by 24 Eq. ( 5):…”

Section: Tunability Analysismentioning

confidence: 99%

Graphene-based tunable tri-band terahertz refractive index sensor

Fu,

Zhang,

Niu

et al. 2024

AIP Advances

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A tunable tri-band terahertz refractive index sensor based on graphene is proposed and designed. The structure of the sensor comprises a gold (Au) substrate layer, a dielectric layer (Topas), and a graphene pattern layer. The numerical simulation results demonstrate that the sensor exhibits three narrowband absorption peaks at 1.68, 3.82, and 4.78 THz, and the corresponding absorption rate can reach 99.9%, 98.0%, and 97.9%, respectively. By adjusting the Fermi level of graphene, the resonant frequency of the sensor can be effectively tuned. Notably, due to the rotational symmetry of the structure, the sensor shows insensitivity to transverse magnetic and transverse electric polarizations of incident light. By varying the refractive index of surrounding analytes, the sensor’s sensitivity and Figure of Merit (FOM) are studied. The sensitivities of the three resonance peaks are 0.59, 1.19, and 1.38 THz/RIU, with corresponding FOM values of 2.57, 3.40, and 6.58, respectively. Furthermore, the feasibility and effectiveness of the designed sensor in practical applications are verified by testing five types of samples. These findings indicate that the proposed sensor has superior performance in sensitivity and selectivity, which makes it have a great potential for applications in the fields of material characterization, environmental monitoring, and biomedicine detection in the terahertz band.

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“…Recently in 2023, Ma et al [42] designed a graphene-based hollow circle structure with a working refractive index range of 1.0-1.5. Building upon this progress, Zhan and Fan [43] increased the sensing refractive index limit to 1.7 with improved sensitivity of 2.0 THz/RIU and an absorption rate of 99.77% using a gold/graphene composite. In a similar vein, there have been several notable works in the field.…”

Section: Introductionmentioning

confidence: 99%

Metamaterial as perfect absorber for high sensitivity refractive index based biosensing applications at infrared frequencies

Mostufa

Yari

Rezaei

et al. 2023

J. Phys. D: Appl. Phys.

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In this paper, we introduce a novel design of a metamaterial unit cell absorber, which is based on a metal/insulator/metal sandwich structure. The design is subjected to comprehensive finite element method (FEM) computational analysis to ensure accurate and reliable results. The proposed metamaterial sandwich structure demonstrates exceptional absorption performance, achieving a nearly perfect absorption rate of 99.996% at the resonance infrared frequency of 39.8 THz. To provide a detailed theoretical explanation of nearly perfect absorption, we employ the effective medium theory, impedance matching, and field distribution analysis. Additionally, we have optimized the structural parameters of the sensor to maximize its absorption peak. This includes optimizing the thickness of the gold (Au) layer (from 0.03 to 0.28 μm), the distance between the L shape corners (from 0.60 to 0.90 μm), and the thickness of SiC dielectric spacer (from 0.20 to 0.45 μm). Furthermore, we showcase the remarkable sensitivity of the proposed metamaterial unit cell in detecting subtle changes in the refractive index through the implementation of a sensing medium setup in our model. Remarkably, we achieve a frequency shift sensitivity of 3.74 THz/RIU, along with a quality factor (Q-factor) of 10.33, for a wide range of refractive indices (1.0 - 2.0). Moreover, for cancer detection, we attain a sensitivity of 3.5 THz/RIU. These findings highlight the exceptional performance of our approach in accurately detecting changes in refractive index, making it a promising candidate for various sensing applications. The novelty of our work lies in the design of a metamaterial unit cell structure. This configuration exhibits several noteworthy features, including wide incident angle (θ) coverage up to 60o, polarization insensitivity, exceptional frequency shift sensitivity, high absorption peaks across a wide range of refractive indices, and the ability to distinguish cancer cells from healthy ones.

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Investigation on the tunable and polarization sensitive three-band terahertz graphene metamaterial absorber

Cited by 5 publications

References 56 publications

Graphene-Based Tunable Dual-Frequency Terahertz Sensor

Graphene-Based Tunable Dual-Frequency Terahertz Sensor

Graphene-based tunable tri-band terahertz refractive index sensor

Metamaterial as perfect absorber for high sensitivity refractive index based biosensing applications at infrared frequencies

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