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Zhang YG, Liu W, Yao HY, Liang LJ, Yan X, Zong MJ, Gao S, Huang CC, Qiu F, Feng ZW, Zhang R, Hu XF, Li ZH, Wang ZQ. Broad/narrowband switchable terahertz absorber based on Dirac semimetal and strontium titanate for temperature sensing. APPLIED OPTICS 2024; 63:1306-1312. [PMID: 38437310 DOI: 10.1364/ao.509826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/17/2024] [Indexed: 03/06/2024]
Abstract
A broadband and narrowband switchable terahertz (THz) absorber based on a bulk Dirac semimetal (BDS) and strontium titanate (STO) is proposed. Narrowband and broadband absorption can be switched by adjusting the Fermi level of the BDS. When the Fermi level of the BDS is 100 meV, the device is an absorber with three narrowband absorption peaks. The frequencies are 0.44, 0.86, and 1.96 THz, respectively, when the temperature of STO is 250 K. By adjusting the temperature of STO from 250 to 500 K, the blue shifts of the frequencies are approximately 0.14, 0.32, and 0.60 THz, respectively. The sensitivities of the three absorption peaks are 0.56, 1.27, and 2.38 GHz/K, respectively. When the Fermi level of the BDS is adjusted from 100 to 30 meV, the device can be switched to a broadband absorber with a bandwidth of 0.70 THz. By adjusting the temperature of STO from 250 to 500 K, the central frequency shifts from 1.40 to 1.79 THz, and the bandwidth broadens from 0.70 to 0.96 THz. The sensitivity of the central frequency is 1.57 GHz/K. The absorber also has a wide range of potential applications in multifunctional tunable devices, such as temperature sensors, stealth equipment, and filters.
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Zheng L, Feng R, Shi H, Li X. Tunable Broadband Terahertz Metamaterial Absorber Based on Vanadium Dioxide and Graphene. MICROMACHINES 2023; 14:1715. [PMID: 37763877 PMCID: PMC10537236 DOI: 10.3390/mi14091715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/22/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023]
Abstract
We propose a dynamically tunable ultra-broadband terahertz metamaterial absorber, which was based on graphene and vanadium oxide (VO2) and numerically demonstrated. The excellent absorption bandwidth almost entirely greater than 90% was as wide as 6.35 THz from 2.30 to 8.65 THz under normal incidence. By changing the conductivity of VO2 from 20 S/m to 3 × 105 S/m, the absorption intensity could be dynamically tuned from 6% to 99%. The physical mechanism of the ultra-wideband absorption is discussed based on the interference cancelation, impedance matching theory, and field distributions, and the influences of the structural parameters on absorption are also discussed. According to the symmetric configuration, the absorption spectra of the considered polarizations were very close to each other, resulting in a polarization-insensitive structure. Such a tunable ultra-broadband absorber may have promising potential in the applications of modulating, cloaking, switching, and imaging technology.
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Affiliation(s)
- Laifang Zheng
- Department of Electrical Engineering, Taiyuan Institute of Technology, Taiyuan 030008, China;
- China Key Laboratory of Micro/Nano Devices and Systems, Ministry of Education, North University of China, Taiyuan 030051, China; (H.S.); (X.L.)
| | - Rui Feng
- China Key Laboratory of Micro/Nano Devices and Systems, Ministry of Education, North University of China, Taiyuan 030051, China; (H.S.); (X.L.)
| | - Huanting Shi
- China Key Laboratory of Micro/Nano Devices and Systems, Ministry of Education, North University of China, Taiyuan 030051, China; (H.S.); (X.L.)
| | - Xuanjing Li
- China Key Laboratory of Micro/Nano Devices and Systems, Ministry of Education, North University of China, Taiyuan 030051, China; (H.S.); (X.L.)
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Zhang YG, Feng ZW, Liang LJ, Yao HY, Wang YR, Xu L, Yan X, Liu W. High-performance dual-tunable terahertz absorber based on strontium titanate and bulk Dirac semimetal for temperature sensing and switching function. APPLIED OPTICS 2023; 62:5822-5829. [PMID: 37707202 DOI: 10.1364/ao.495749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/05/2023] [Indexed: 09/15/2023]
Abstract
In this study, a perfect metamaterial absorber based on strontium titanate and bulk Dirac semimetals is proposed. When the temperature of strontium titanate was 300K, the dual-band absorptions were 99.74% and 99.99% at 1.227 and 1.552 THz, respectively. The sensitivities based on a transverse magnetic (TM) wave were 0.95 and 1.22 GHz/K; the sensitivity based on a transverse electric (TE) wave was 0.76 GHz/K. The TE and TM waves were modulated by inserting a bulk Dirac semimetal between the concave and convex devices. The modulation depth of the TE wave was 97.9% at 1.1 THz; the extinction ratio was 16.9 dB. The modulation depth of the TE wave at 1.435 THz was 95.9%; the extinction ratio was 13.89 dB. The TM wave modulation depth at 1.552 THz was 95.9%; the extinction ratio was 13.98 dB. Irrespective of a TE or TM wave, the terahertz absorber has good switching and temperature-sensing performance based on strontium titanate and bulk Dirac semimetals as well as broad application prospects in temperature sensing and switching devices.
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Didari-Bader A, Saghaei H. Penrose tiling-inspired graphene-covered multiband terahertz metamaterial absorbers. OPTICS EXPRESS 2023; 31:12653-12668. [PMID: 37157421 DOI: 10.1364/oe.485847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In this work, we propose two different graphene-covered nanostructured metamaterial absorbers inspired by Penrose tiling. These absorbers allow spectrally tunable absorption within the terahertz spectrum corresponding to 0.2-20 THz. We have conducted finite-difference time-domain analyses to determine the tunability of these metamaterial absorbers. The proposed structures, Penrose models 1 and 2, perform differently from each other due to their design characteristics. Penrose model 2 reaches a perfect absorption at 8.58 THz. In addition, the relative absorption bandwidth calculated at full-wave at half-maximum in Penrose model 2 varies between 5.2% and 9.4%, which characterizes the metamaterial absorber as a wideband absorber. Also, we can observe that as we increase the Fermi level of graphene from 0.1 to 1 eV, the absorption bandwidth and relative absorption bandwidth both increase. Our findings show the high tunability of both models through varying graphene's Fermi level, the graphene's thickness, the substrate's refractive index, and the proposed structures' polarization. We can further observe multiple tunable absorption profiles that may find applications in designer infrared absorbers, optoelectronic devices, and THz sensors.
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Zhang YG, Zhang R, Liang LJ, Yao HY, Yan X, Huang CC, Ying KH. Multifunctional terahertz absorber based on the Dirac semimetal and vanadium dioxide. APPLIED OPTICS 2023; 62:813-819. [PMID: 36821288 DOI: 10.1364/ao.478846] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/07/2022] [Indexed: 06/18/2023]
Abstract
In this paper, a multifunctional terahertz (THz) absorber based on Dirac semimetal and vanadium dioxide (V O 2) is proposed. By modulating the temperature of V O 2, the absorber can be switched between the narrow band and wide band. When V O 2 is in the metallic state, the absorber has a broadband absorption effect with a bandwidth of approximately 4 THz. It has the advantages of insensitivity to polarization and wide-angle absorption. When V O 2 is in the insulating state, the absorber has two absorption peaks with absorptivity exceeding 90% and sensitivities of 297.7 and 402 GHz/RIU, and thus can be used as a highly sensitive sensor for cell detection. When the Fermi level of the Dirac semimetal is changed, the absorption characteristics can be modulated. The absorber has broad application prospects in multifunctional modulated devices.
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Seo D, Lee JK, Park GC. Active Fano resonance switch using dual-layer graphene in an embedded dielectric metasurface. OPTICS EXPRESS 2022; 30:22247-22259. [PMID: 36224927 DOI: 10.1364/oe.461706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/20/2022] [Indexed: 06/16/2023]
Abstract
We propose an active optical Fano switch (OFS) based on an embedded dielectric metasurface (EDM) including dual-layer graphene (DLG). An EDM is a dielectric grating overlapped by two cladding layers, and it excites a Fano resonance. DLG is positioned inside the upper cladding layer to maximize light-graphene interaction. Thus, with a small change of the chemical potential (µc) of graphene, a resonance wavelength is tuned to switch the OFS on and off. First, a red-parity asymmetric Fano resonance is realized, and a sharp asymmetric lineshape is achieved by controlling the structural parameters of the EDM and the interaction between the Fano resonance and additional weak Fabry-Perot interference for efficient switching. The distance of a peak-to-dip wavelength (Δλp-d) and the change of chemical potential (Δµc) for switching is analyzed by varying the duty cycle (DC) and grating thickness (tg) of the EDM. Furthermore, switching contrast as a figure of merit (FoM) is analyzed. With DC of 0.5 and tg of 70 nm, the OFS requires Δλp-d of 7.3 nm and Δµc of 0.25 eV. The FoM of 0.97 is achieved. By adjusting the two parameters, the switching condition is tuned. In the case of a blue parity, the effect of the two parameters exhibits a similar trend to that of the red parity. The FoM, however, is lower due to the reversed parity.
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Feng H, Zhang Z, Zhang J, Fang D, Wang J, Liu C, Wu T, Wang G, Wang L, Ran L, Gao Y. Tunable Dual-Broadband Terahertz Absorber with Vanadium Dioxide Metamaterial. NANOMATERIALS 2022; 12:nano12101731. [PMID: 35630953 PMCID: PMC9143179 DOI: 10.3390/nano12101731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/14/2022] [Accepted: 05/17/2022] [Indexed: 11/24/2022]
Abstract
A dual broadband terahertz bifunction absorber that can be actively tuned is proposed. The optical properties of the absorber were simulated and numerically calculated using the finite-difference time-domain (FDTD) method. The results show that when the conductivity of vanadium dioxide is less than σ0=8.5×103 S/m, the absorptance can be continuously adjusted between 2% and 100%. At vanadium dioxide conductivity greater than σ0=8.5×103 S/m, the absorption bandwidth of the absorber can be switched from 3.4 THz and 3.06 THz to 2.83 THz and none, respectively, and the absorptance remains above 90%. This achieves perfect modulation of the absorptance and absorption bandwidth. The physical mechanism of dual-broadband absorptions and perfect absorption is elucidated by impedance matching theory and electric field distribution. In addition, it also has the advantage of being polarization insensitive and maintaining stable absorption at wide angles of oblique incidence. The absorber may have applications in emerging fields such as modulators, stealth and light-guided optical switches.
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Affiliation(s)
- Hengli Feng
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Zuoxin Zhang
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Jingyu Zhang
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Dongchao Fang
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Jincheng Wang
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Chang Liu
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Tong Wu
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Guan Wang
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Lehui Wang
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Lingling Ran
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
| | - Yang Gao
- School of Electronic Engineering, Heilongjiang University, Harbin 150080, China; (H.F.); (Z.Z.); (J.Z.); (D.F.); (J.W.); (C.L.); (T.W.); (G.W.); (L.W.); (L.R.)
- Heilongjiang Provincial Key Laboratory of Metamaterials Physics and Device, School of Electronic Engineering, Heilongjiang University, Harbin 150080, China
- Correspondence:
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Cheng R, Zhou Y, Liu J, Hu S, Liu H, Pan J, Huang W, He X, Liang B, Zhang L. Independently tunable multi-band terahertz absorber based on graphene sheet and nanoribbons. OPTICS EXPRESS 2022; 30:3893-3902. [PMID: 35209638 DOI: 10.1364/oe.450606] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
A multi-band terahertz (THz) absorber based on graphene sheet and nanoribbons is proposed and investigated. In the studied frequency range, five absorption peaks are observed, with four originate from lateral Fabry-Perot resonance (LFPR) and one originates from guided-mode resonance (GMR). The LFPR and GMR peaks behave differently when geometric parameters are adjusted, which makes independent tuning possible. When period increases, the GMR peak red shifts and the frequencies of LFPR peaks remain almost unchanged. On the contrary, as nanoribbon width increases, the frequency of GMR remains almost unchanged while that of LFPRs decrease significantly. With increasing top dielectric layer thickness, the LFPR peaks blue shift while the GMR peak red shifts. In addition, the absorber has the merit of multi-band high absorptivity and frequency stability under large angle oblique incidence. The proposed terahertz absorber may benefit the areas of medical imaging, sensing, non-destructive testing, THz communications and other applications.
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Jiang W, Chen T. A five-band absorber based on graphene metamaterial for terahertz ultrasensing. NANOTECHNOLOGY 2022; 33:165503. [PMID: 35016165 DOI: 10.1088/1361-6528/ac4a29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
We design and propose a five-band absorber based on graphene metamaterial for the terahertz (THz) sensing field. The localized surface plasmon resonances of patterned graphene are excited, contributing to five tunable ultra-narrow absorption peaks, which are specified by the electric field distributions. Moreover, the absorber is insensitive to different polarization modes and incident angles. When increasing the Fermi level of the patterned graphene, which is composed of a round ring and a square ring connected by four thin wires, the resonant frequencies exhibit distinct blue shifts. For refractive index sensing, due to the addition of a continuous dielectric groove, the theoretical results show that the maximum averaged normalized sensitivity,Qfactor, and FOM can reach 0.647 RIU-1(refractive index unit, RIU), 355.94, and 215.25 RIU-1, indicating that the sensing performances are further enhanced compared with previous works. As a result, the proposed structure may provide a new method to realize ultrasensing in the THz region.
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Affiliation(s)
- Weijie Jiang
- Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, School of Electronic Engineering and Automation, Guilin University of Electronic Technology, Guilin 541000, People's Republic of China
| | - Tao Chen
- Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, School of Electronic Engineering and Automation, Guilin University of Electronic Technology, Guilin 541000, People's Republic of China
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Wu T, Shao Y, Ma S, Wang G, Gao Y. Broadband terahertz absorber with tunable frequency and bandwidth by using Dirac semimetal and strontium titanate. OPTICS EXPRESS 2021; 29:7713-7723. [PMID: 33726267 DOI: 10.1364/oe.418679] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
A bifunctional broadband absorber in the terahertz band based on patterned bulk Dirac semimetal (BDS) and strontium titanate (STO) is proposed. The properties of the absorber are investigated using the finite-difference time-domain (FDTD) method. The results show that the width of absorption can be modulated from 0.59 THz to 0.7 THz when the Fermi energy of the BDS is independently shifted from 40 meV to 50 meV. By tuning the temperature from 250 K to 400K, the center frequency of the broadband absorption spectrum can be changed from 1.311 THz to 1.505 THz, and the absorption bandwidth broadens from 0.66 THz to 0.81 THz. In addition, the simulation results show that the absorber is insensitive to electromagnetic wave polarization, and can still maintain a stable broadband absorption effect when the oblique incidence is within 40° for TE and TM modes. Based on the impedance matching theory, the physical mechanism of the broadband absorption is analyzed theoretically. This work can provide an alternative way to design high-performance multifunctional tunable terahertz devices.
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Pourmand M, Choudhury PK, Mohamed MA. Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters. Sci Rep 2021; 11:3603. [PMID: 33574491 PMCID: PMC7878520 DOI: 10.1038/s41598-021-83304-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 02/01/2021] [Indexed: 01/30/2023] Open
Abstract
Investigation was made of the optical response of metal-dielectric stacks-based cavity structures embedded with graphene microheaters for the purpose of perfect absorption. The absorber configuration exploits the Ge2Sb2Te5 (GST) phase changing medium, and the effects of different parametric and operational conditions on the absorption spectra were explored. The refractive indices of GST layers can be manipulated by the external electrical pulses applied to microheaters. The amplitude and duration of electrical pulses define the crystallinity ratio of the used GST mediums. The results revealed achieving perfect absorption (> 99%) in the visible and infrared (IR) regimes of the electromagnetic spectrum upon incorporating two thin GST layers of different thicknesses (in the stack) in the amorphous state. The proposed configuration showed the capability of introducing independent transition state (amorphous and/or crystalline) for each GST layer-the visible regime could be extended to the IR regime, and the perfect absorption peak in the IR regime could be broadened and red-shifted. It is expected that the structure would find potential applications in active photonic devices, infrared imaging, detectors and tunable absorbers.
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Affiliation(s)
- M Pourmand
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, UKM, 43600, Bangi, Selangor, Malaysia
| | - P K Choudhury
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, UKM, 43600, Bangi, Selangor, Malaysia.
| | - Mohd Ambri Mohamed
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, UKM, 43600, Bangi, Selangor, Malaysia
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Lin J, Chen H, Ma D, Gong Y, Li Z, Li D, Song Y, Zhang F, Li J, Wang H, Zhang Y, Zhang H. Band structure tuning of α-MoO 3 by tin intercalation for ultrafast photonic applications. NANOSCALE 2020; 12:23140-23149. [PMID: 33191417 DOI: 10.1039/d0nr05935h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
van der Waals (vdW) transition metal oxides have attracted extensive attention due to their intriguing physical and chemical properties. However, primary drawbacks of these materials are the lack of band structure tunability and substandard optical properties, which severely hinder their implementation in nanophotonic applications. Atomic intercalation is an emerging structural engineering approach for two-dimensional vdW materials to engineer the atomic structure and modify the optical properties, thereby broadening their range of applications. Herein, we synthesized tin-intercalated ultrathin α-MoO3 (Sn-MoO3) nanoribbons via chemical intercalation method and then investigated the broadband nonlinear optics (NLO) of stable few-layer α-MoO3 by performing a Z-scan laser measurement and femtosecond-resolved transient absorption (TA) spectroscopy. Sn-MoO3 showed a stable structure of Mo-O-Sn-O-Mo and a shorter relaxation time than pristine MoO3, indicating the accelerated recombination process of electrons and holes. Furthermore, Sn-MoO3 nanoribbons were used as an optical saturable absorber for ultrafast photonics; a highly stable femtosecond laser with a pulse width of 467 fs was generated from a single-mode fiber in the telecommunication band (1550 nm). These results indicate that atomic intercalation is an effective way to modulate the band structure and nonlinear optical properties of α-MoO3, which hold a great potential in the generation of ultrafast mode-locked laser pulses for optical communication technologies.
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Affiliation(s)
- Jiamei Lin
- Institute of Microscale Optoelectronics, Collaborative Innovation Center for Optoelectronic Science and Technology and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen 518060, P. R. China.
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Wang T, Yan F, Wang R, Tian F, Li L. Tunable plasmon-induced transparency with a dielectric grating-coupled graphene structure for slowing terahertz waves. APPLIED OPTICS 2020; 59:7179-7185. [PMID: 32902480 DOI: 10.1364/ao.399286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
We present a tunable plasmon-induced transparency (PIT) structure that is composed of dielectric grating and a graphene system to manipulate terahertz (THz) waves. The graphene system consists of a graphene sheet and a graphene ribbon layer, with a spacer between them. By exploiting the diffraction coupling of THz wave with dielectric grating, graphene plasmonic resonance is efficiently excited on both graphene sheet and graphene ribbons. This leads to the surface plasmon mode of the graphene sheet and the localized plasmon mode of the graphene ribbons. The coupling between the two-plasmon modes via near-field destructive interference generates a strong PIT effect with slowing the group velocity of THz waves. A group delay over 0.2 ps and group index beyond 170 can be achievable. The group slowing effect is dynamically tunable with varying the Fermi level of graphene. The work suggests a promising scheme for on-chip graphene slow-wave devices at the THz regime.
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Bao Z, Tang Y, Hu ZD, Zhang C, Balmakou A, Khakhomov S, Semchenko I, Wang J. Inversion Method Characterization of Graphene-Based Coordination Absorbers Incorporating Periodically Patterned Metal Ring Metasurfaces. NANOMATERIALS 2020; 10:nano10061102. [PMID: 32498313 PMCID: PMC7353306 DOI: 10.3390/nano10061102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/27/2020] [Accepted: 05/30/2020] [Indexed: 11/16/2022]
Abstract
In this paper, we propose a tunable coordinated multi-band absorber that combines graphene with metal–dielectric–metal structures for the realization of multiple toward perfect absorption. The parametric inversion method is used to extract the equivalent impedance and explain the phenomena of multiple-peak absorption. With the change of the Fermi level, equivalent impedances were extracted, and the peculiarities of the individual multiple absorption peaks to change were determined. By changing the structure parameters of gold rings, we obtain either multiple narrow-band absorption peaks or a broadband absorption peak, with the bandwidth of 0.8 μm where the absorptance is near 100%. Therefore, our results provide new insights into the development of tunable multi-band absorbers and broadband absorbers that can be applied to terahertz imaging in high-performance coordinate sensors and other promising optoelectronic devices.
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Affiliation(s)
- Zhiyu Bao
- School of Science, Jiangnan University, Wuxi 214122, China; (Z.B.); (Y.T.); (Z.-D.H.); (J.W.)
| | - Yang Tang
- School of Science, Jiangnan University, Wuxi 214122, China; (Z.B.); (Y.T.); (Z.-D.H.); (J.W.)
| | - Zheng-Da Hu
- School of Science, Jiangnan University, Wuxi 214122, China; (Z.B.); (Y.T.); (Z.-D.H.); (J.W.)
| | - Chengliang Zhang
- School of Science, Jiangnan University, Wuxi 214122, China; (Z.B.); (Y.T.); (Z.-D.H.); (J.W.)
- Correspondence:
| | - Aliaksei Balmakou
- Departments of Optics and General Physics, Francisk Skorina Gomel State University, Sovetskaya Str. 104, 246019 Gomel, Belarus; (A.B.); (S.K.); (I.S.)
| | - Sergei Khakhomov
- Departments of Optics and General Physics, Francisk Skorina Gomel State University, Sovetskaya Str. 104, 246019 Gomel, Belarus; (A.B.); (S.K.); (I.S.)
| | - Igor Semchenko
- Departments of Optics and General Physics, Francisk Skorina Gomel State University, Sovetskaya Str. 104, 246019 Gomel, Belarus; (A.B.); (S.K.); (I.S.)
| | - Jicheng Wang
- School of Science, Jiangnan University, Wuxi 214122, China; (Z.B.); (Y.T.); (Z.-D.H.); (J.W.)
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
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Xu KD, Li J, Zhang A, Chen Q. Tunable multi-band terahertz absorber using a single-layer square graphene ring structure with T-shaped graphene strips. OPTICS EXPRESS 2020; 28:11482-11492. [PMID: 32403659 DOI: 10.1364/oe.390835] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/29/2020] [Indexed: 05/21/2023]
Abstract
We numerically demonstrate a tunable dual-band terahertz metamaterial absorber (MA) with near-unity absorption using single-layer square graphene ring structure with T-shaped graphene strips. By periodically loading four T-shaped graphene strips to the square graphene ring periodic array without additionally increasing the size of MA device, the pre-existing resonant frequency will have a red shift and simultaneously a new resonance will be generated at higher frequency for achieving a dual-band MA. The two absorption peaks can be tuned to the resonant frequencies of interest by varying the parameters of the square graphene ring and T-shaped graphene strips. The operating frequency of the absorption spectrum can be also manipulated by adjusting the chemical potential of graphene, without changing their geometric parameters. Additionally, numerical results show that the proposed MA possesses polarization-independent and incident-angle-insensitive properties. To further extend the proposed structure's application with more absorption peaks, a tri-band MA is investigated through adding four more T-shaped graphene strips based on the dual-band absorber configuration. Therefore, our research work will be a good candidate for the design of various graphene-based tunable multi-band absorbers at different frequency regions with potential applications in optoelectronic devices and systems.
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Li Y, Liu Z, Pan P, Liu X, Fu G, Liu Z, Luo H, Liu G. Semiconductor-nanoantenna-assisted solar absorber for ultra-broadband light trapping. NANOSCALE RESEARCH LETTERS 2020; 15:76. [PMID: 32270307 PMCID: PMC7142205 DOI: 10.1186/s11671-020-03311-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
Light trapping is an important performance of ultra-thin solar cells because it cannot only increase the optical absorption in the photoactive region but it also allows for the efficient absorption with very little materials. Semiconductor-nanoantenna has the ability to enhance light trapping and raise the transfer efficiency of solar energy. In this work, we present a solar absorber based on the gallium arsenide (GaAs) nanoantennas. Near-perfect light absorption (above 90%) is achieved in the wavelength which ranges from 468 to 2870 nm, showing an ultra-broadband and near-unity light trapping for the sun's radiation. A high short-circuit current density up to 61.947 mA/cm2 is obtained. Moreover, the solar absorber is with good structural stability and high temperature tolerance. These offer new perspectives for achieving ultra-compact efficient photovoltaic cells and thermal emitters.
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Affiliation(s)
- Yuyin Li
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China
| | - Zhengqi Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China.
| | - Pingping Pan
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China
| | - Xiaoshan Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China
| | - Guolan Fu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China
| | - Zhongmin Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China
| | - Haimei Luo
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China
| | - Guiqiang Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, 330022, China.
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