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Xu Z, Li Y, Han B, Wang Y, Yuan Q, Li Y, He W, Hao J, Wu L, Yao J. All-Silicon Polarization-Insensitive Metamaterial Absorber in the Terahertz Range. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2098. [PMID: 38730908 PMCID: PMC11084379 DOI: 10.3390/ma17092098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/22/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024]
Abstract
All-silicon terahertz absorbers have attracted considerable interest. We present a design and numerical study of an all-silicon polarization-insensitive terahertz metamaterial absorber. The meta-atoms of the metamaterial absorber are square silicon rings which can be viewed as gratings. By properly optimizing the structure of the meta-atom, we achieve a broadband absorptivity that is above 90% ranging from 0.77 THz to 2.53 THz, with a relative bandwidth of 106.7%. Impedance matching reduces the reflection of the terahertz waves and the (0, ±1)-order diffraction induce the strong absorption. The absorption of this absorber is insensitive to the polarization of the terahertz wave and has a large incident angle tolerance of up to 60 degrees. The all-silicon metamaterial absorber proposed here provides an effective way to obtain broadband absorption in the terahertz regime. Metamaterial absorbers have outstanding applications in terahertz communication and imaging.
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Affiliation(s)
- Zongcheng Xu
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Yujie Li
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Bin Han
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Yue Wang
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Quan Yuan
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Yanan Li
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Weiyan He
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Junhua Hao
- Department of Physics, Tianjin Renai College, Tianjin 301636, China; (Y.L.); (B.H.); (Y.W.); (Q.Y.); (Y.L.); (W.H.); (J.H.)
| | - Liang Wu
- Key Laboratory of Opto-Electronics Information Science and Technology, Ministry of Education, Institute of Laser and Opto-Electronics, Tianjin University, Tianjin 300072, China;
| | - Jianquan Yao
- Key Laboratory of Opto-Electronics Information Science and Technology, Ministry of Education, Institute of Laser and Opto-Electronics, Tianjin University, Tianjin 300072, China;
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Zhong Z, Wu Q, Ling F, Zhang B. Method for designing ultra-wideband absorbers based on water-filled Fabry-Perot cavity with continuously varying cavity length. OPTICS LETTERS 2023; 48:5591-5594. [PMID: 37910710 DOI: 10.1364/ol.498354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/06/2023] [Indexed: 11/03/2023]
Abstract
Broadband and efficient terahertz (THz) absorbers are crucial for various applications in sensing, imaging, detecting, and modulation. Although recent studies have reported a series of THz metamaterials for enhanced absorption, achieving high absorption across the entire ultrabroad terahertz band remains challenging. We propose a novel, to the best of our knowledge, method to design ultra-wideband terahertz absorbers using a water-filled Fabry-Perot cavity with continuously varying cavity length. Our design achieves over 90% absorption across an ultrabroad terahertz band ranging from 0.26 to 30 THz. Furthermore, the design method can be extended to the visible, infrared, and microwave regimes. We believe that our method will inspire further studies and applications of ultra-wideband absorbers.
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Cui E, Wan Z, Ke C, Wu C, Wang D, Lei C. Flexible and efficient fabrication of a terahertz absorber by single-step laser direct writing. OPTICS EXPRESS 2022; 30:42944-42955. [PMID: 36523004 DOI: 10.1364/oe.468753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/30/2022] [Indexed: 06/17/2023]
Abstract
Laser direct writing (LDW) is a promising candidate for the fabrication of all-dielectric THz absorbers for its high flexibility and material compatibility. However, multi-step processing or multi-layer materials are required to compensate for the nonideal features of LDW to realize good absorption performance. To further explore the potential of LDW in flexible and cost-effective THz absorber fabrication, in this work, we demonstrate a design method of THz absorbers fully considering and utilizing the characteristics of laser processing. Specifically, we first numerically analyze that by properly combining basic structures processed by single-step LDW, good and adjustable absorption performance can be achieved on a single-layer substrate. Then we experimentally fabricate THz absorbers by processing periodic composite structures, which are combined by grooves and circular holes, on single-layer doped silicon using LDW. Experimental results show that our method can fabricate THz absorbers at a speed of 3.3 mm2/min with an absorptivity above 90% over a broadband of 1.8-3 THz. Our method provides a promising solution for the flexible and efficient fabrication of all-dielectric broadband THz absorbers.
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You X, Upadhyay A, Cheng Y, Bhaskaran M, Sriram S, Fumeaux C, Withayachumnankul W. Ultra-wideband far-infrared absorber based on anisotropically etched doped silicon. OPTICS LETTERS 2020; 45:1196-1199. [PMID: 32108804 DOI: 10.1364/ol.382458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/18/2020] [Indexed: 06/10/2023]
Abstract
Far-infrared absorbers exhibiting wideband performance are in great demand in numerous applications, including imaging, detection, and wireless communications. Here, a nonresonant far-infrared absorber with ultra-wideband operation is proposed. This absorber is in the form of inverted pyramidal cavities etched into moderately doped silicon. By means of a wet-etching technique, the crystallinity of silicon restricts the formation of the cavities to a particular shape in an angle that favors impedance matching between lossy silicon and free space. Far-infrared waves incident on this absorber experience multiple reflections on the slanted lossy silicon side walls, being dissipated towards the cavity bottom. The simulation and measurement results confirm that an absorption beyond 90% can be sustained from 1.25 to 5.00 THz. Furthermore, the experiment results suggest that the absorber can operate up to at least 21.00 THz with a specular reflection less than 10% and negligible transmission.
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Xiao D, Zhu M, Sun L, Zhao C, Wang Y, Tong Teo EH, Hu F, Tu L. Flexible Ultra-Wideband Terahertz Absorber Based on Vertically Aligned Carbon Nanotubes. ACS APPLIED MATERIALS & INTERFACES 2019; 11:43671-43680. [PMID: 31640338 DOI: 10.1021/acsami.9b14428] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ultra-wideband absorbers have been extensively used in wireless communications, energy harvesting, and stealth applications. Herein, with the combination of experimental and theoretical analyses, we develop a flexible ultra-wideband terahertz absorber based on vertically aligned carbon nanotubes (VACNTs). Measured results show that the proposed absorber is able to work efficiently within the entire THz region (e.g., 0.1-3.0 THz), with an average power absorptance of >98% at normal incidence. The absorption performance remains at a similar level over a wide range of incident angle up to 60°. More importantly, our devices can function normally, even after being bent up to 90° or after 300 bending cycles. The total thickness of the device is about 360 μm, which is only 1/8 of the wavelength for the lowest evaluated frequency of 0.1 THz. The new insight into the VACNT materials paves the way for applications such as radar cross-section reduction, electromagnetic interference shielding, and flexible sensing because of the simplicity, flexibility, ultra-wideband operation, and large-scale fabrication of the device.
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Affiliation(s)
- Dongyang Xiao
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , Hubei , China
| | - Minmin Zhu
- School of Electrical and Electronic Engineering , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798 , Singapore
- Temasek Laboratories , Research Techno Plaza, 50 Nanyang Drive , Singapore 637553 , Singapore
| | - Leimeng Sun
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , Hubei , China
| | - Chun Zhao
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , Hubei , China
| | - Yurong Wang
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , Hubei , China
| | - Edwin Hang Tong Teo
- School of Electrical and Electronic Engineering , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798 , Singapore
| | - Fangjing Hu
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , Hubei , China
| | - Liangcheng Tu
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , Hubei , China
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