Article
Chemistry, Multidisciplinary
Yumin Gong, Baogang Quan, Fangrong Hu, Longhui Zhang, Mingzhu Jiang, Shangjun Lin
Summary: This study experimentally demonstrates a graphene metasurface for THz field enhancement by adjusting the conductivity of the graphene patch. The results show enhancement of the THz field and provide a foundation for exploring THz-matter interactions and nonlinear optics.
Article
Physics, Multidisciplinary
Yafeng Lu, Chen Wang, Shiqiang Zhao, Yongzheng Wen
Summary: Graphene is proposed as a platform for THz devices, and a graphene-based THz metasurface using cut-wire arrays is introduced for magnetic manipulation of THz waves. This structure allows efficient tuning of the metasurface response, making it suitable for applications such as compact THz modulators and magnetic field sensors.
FRONTIERS IN PHYSICS
(2021)
Article
Chemistry, Physical
Yumin Gong, Fangrong Hu, Mingzhu Jiang, Longhui Zhang, Yingchang Zou, Guobao Jiang, Yongchen Liu
Summary: This study presents a THz binary encoder based on graphene metasurface, which achieves separate modulation of each passband by electrically adjusting the Fermi energy of graphene. The function of THz frequency range binary coding is realized, laying a new foundation for the development of multifunctional integrated THz devices.
Article
Materials Science, Multidisciplinary
Zhihui He, Lingqiao Li, Huqiang Ma, Lihui Pu, Hui Xu, Zao Yi, Xinliang Cao, Wei Cui
Summary: The study presents a highly sensitive sensor based on a graphene metasurface that can achieve tunable graphene plasmon-induced transparency in the terahertz band, providing high sensitivity and figure of merit for sensor performance.
RESULTS IN PHYSICS
(2021)
Article
Chemistry, Physical
Qun Xie, Linhui Guo, Zexuan Zhang, Panpan Gao, Mei Wang, Feng Xia, Kun Zhang, Peng Sun, Lifeng Dong, Maojin Yun
Summary: A monolayer terahertz graphene metasurface has been designed to achieve tunable plasmon-induced transparency effect in two perpendicular polarization directions based on surface plasmon polariton resonance. By adjusting the Fermi levels of graphene, penta-frequency and dual-frequency switches can be easily implemented, with excellent performances and high sensitivity. The designed metasurface also exhibits a good slow light effect, making it potentially useful for applications in switches, sensors, and slow-light devices.
APPLIED SURFACE SCIENCE
(2022)
Article
Optics
Shengnan Guan, Jierong Cheng, Zhiyu Tan, Fei Fan, Yunyun Ji, Shengjiang Chang
Summary: Single-pixel imaging is an attractive technique in the terahertz band where array detectors are not mature. Metasurfaces are usually used to enhance the modulation depth in the spatial light modulator. This study utilizes the flexible spectral response of pixelated metasurface resonators to encode different spatial masks into different frequency windows without active materials and external stimuli. The measurements are obtained in parallel through a single terahertz signal, allowing the reconstruction of high-fidelity images with plenty of choices of frequency windows.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Chemistry, Physical
Maosheng Yang, Tengteng Li, Ju Gao, Xin Yan, Lanju Liang, Haiyun Yao, Jie Li, Dequan Wei, Meng Wang, Tong Zhang, Yunxia Ye, Xiaoxian Song, Haiting Zhang, Yunpeng Ren, Xudong Ren, Jianquan Yao
Summary: The study reveals that graphene as a material for terahertz metasurfaces can modulate higher-order Fano resonance at the Dirac point under external stimuli. Accompanied by Fermi level shifts, higher-order Fano resonances exhibit distinct processes of disappearance, appearance, and re-appearance during modulation. Furthermore, a small change in bias voltage or power density can achieve a modulation depth of 90%.
APPLIED SURFACE SCIENCE
(2021)
Article
Optics
Shuvajit Roy, Kapil Debnath
Summary: In this paper, a new method of tuning graphene-based terahertz (THz) metasurfaces is proposed using the electromechanical method. By supporting a free-standing graphene layer on an oxide grating on a gold substrate, the resonance wavelength of the metasurface can be shifted by causing a deflection in the free-standing regions of the graphene layer through the potential difference between the graphene layer and the gold substrate. Numerical simulation shows continuous tunability of the resonant frequency over a frequency range of 0.5 THz for an applied external potential of only 20 V. The application of the proposed metasurface in THz modulation is also demonstrated.
OPTICS COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Guibin Li, Guocui Wang, Yan Zhang, Jingling Shen, Bo Zhang
Summary: The combination of graphene and perovskite has attracted a lot of attention due to its excellent photoelectric properties for manipulating light-matter interactions. The integration of graphene and perovskite with a metasurface is proposed to enhance the metasurface device's performance. In this study, a tunable terahertz graphene-perovskite metasurface is demonstrated, showing significant reduction in transmission and manipulation of the Fano resonance mode under 780 nm laser excitation. Experimental results are verified using finite-difference time-domain simulation.
NANOSCALE ADVANCES
(2023)
Article
Chemistry, Multidisciplinary
Guibin Li, Guocui Wang, Tingting Yang, Yan Zhang, Jingling Shen, Bo Zhang
Summary: This study investigates a graphene-based terahertz negative-conductivity metasurface controlled by an external bias voltage. The interaction between the metasurface and monolayer graphene weakens the resonance mode intensity under passive conditions. However, under active conditions, graphene as an active load enhances the THz transmission and gradually recovers the resonance intensity, resulting in a negative-conductivity effect.
NANOSCALE ADVANCES
(2022)
Article
Materials Science, Multidisciplinary
Yixuan Wang, Wei Cui, Huqiang Ma, Hui Xu, Zao Yi, Xinliang Cao, Xincheng Ren, Zhihui He
Summary: In this paper, a n-shaped graphene metasurface is proposed to achieve plasmon induced transparency (PIT) and an outstanding slow-light effect. The convenient modulation for PIT can be realized through Fermi level and carrier mobility. Additionally, a developed coupled mode theory (CMT) is established to demonstrate the optical responses of the metasurface.
RESULTS IN PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Haiyun Yao, Maosheng Yang, Xin Yan, Lanju Liang, Zhaoqing Sun, Qili Yang, Tongling Wang, Xiaofei Hu, Ziqun Wang, Zhenhau Li, Meng Wang, Kaikai Lv, Yaru Wang, Jianquan Yao
Summary: This article presents a novel flexible terahertz biosensor that utilizes electromagnetic-induced transparency-like metasurfaces and patterned graphene for multidimensional ultra-sensitive detection of plant protein. With changes in frequencies and amplitude, the biosensor is capable of detecting plant protein molecules with a minimum detection limit of 42.3 pg/mL.
RESULTS IN PHYSICS
(2022)
Article
Physics, Multidisciplinary
Hailin Ren, Shijun Ji, Ji Zhao, Handa Dai
Summary: A plasmon-induced terahertz metamaterial absorber is introduced, using a gold bottom layer to block the transmission of terahertz waves, with a topas layer separating the pattern layer and ground layer. The absorber exhibits a 90% absorption bandwidth frequency range of 4.6-7.7 THz, with an average absorption rate of 97.6% in this range. It has polarization insensitivity due to its geometric symmetry, and can maintain over 80% absorption even at an incidence angle of 60 degrees. The absorber also shows good linear frequency shift with refractive index change, with a sensitivity of 1100 GHz per refractive index unit (GHz/RIU), making it suitable for complex electromagnetic scenarios or as a sensing element.
Article
Optics
Yuyu Li, Roberto Paiella
Summary: Graphene plasmonics is used to extend metasurface technology to the terahertz spectral region, providing active tunability. A comprehensive design platform is introduced for the development of THz metasurfaces capable of complex wavefront manipulation functionalities. This approach is compatible with graphene grown by chemical vapor deposition and shows promise for a wide range of THz technologies.
Article
Nanoscience & Nanotechnology
Nadzeya Valynets, Alesia G. Paddubskaya, Vitalii Sysoev, Dmitriy Gorodetskiy, Lyubov G. Bulusheva, Alexander Okotrub
Summary: We propose a novel laser treatment technique for fabricating grating metasurfaces using fluorinated graphene (FG) films, which significantly enhances their terahertz transmission properties. The treatment transforms the insulating FG into conductive material, resulting in a DC conductivity of 170 S·m(-1) in the treated areas. The resonance transmittance of the metasurfaces, studied using THz time-domain spectroscopy in the 100 GHz-1 THz frequency range, shows enhancement and tunability by changing the metasurface geometry. The fabricated metasurfaces also demonstrate efficient narrowband polarization rotation of 50 degrees.
Article
Automation & Control Systems
Zheng Liu, Fu Zhang, Xiaoping Hong
Summary: This article introduces a robotic lidar sensor based on incommensurable scanning to address the manufacturing difficulty of traditional lidars, with unique features and advantages for robotic applications.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2022)
Editorial Material
Multidisciplinary Sciences
Sungho Jeon, Sang-Yeon Hwang, Jim Ciston, Karen C. Bustillo, Bryan W. Reed, Sukjoon Hong, Alex Zettl, Woo Youn Kim, Peter Ercius, Jungwon Park, Won Chul Lee
Summary: Yu et al. suggested improvements to our experimental calculations, but these suggestions raise concerns of misinterpretation and overinterpretation. We believe that the original calculation is sufficient to support our claim.
Article
Robotics
Wen Yang, Zheng Gong, Baifu Huang, Xiaoping Hong
Summary: This paper proposes a lidar and camera fusion approach to correct distortion in oscillating lidars, and utilizes a probabilistic Kalman-filter approach to track moving objects. The method outperforms other approaches on real road data and has been open sourced.
IEEE ROBOTICS AND AUTOMATION LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Derek Popple, Mikhail Shekhirev, Chunhui Dai, Paul Kim, Katherine Xiaoxin Wang, Paul Ashby, Brett A. Helms, Yury Gogotsi, Thomas P. Russell, Alex Zettl
Summary: Liquid electronics offer the potential for flexible redesign and efficient recycling by employing simple liquid phase chemistries. In this study, all-liquid electrically conductive sheets, wires, and functional devices were demonstrated using self-assembled MXene nanoparticles at liquid-liquid interfaces. These assemblies combine the high conductivity of MXene nanosheets with the reconfigurability and controllable form of structured liquids.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
A. K. Schuster, K. Voigt, B. Klemmed, N. J. Hartley, J. Luetgert, M. Zhang, C. Baehtz, A. Benad, C. Brabetz, T. Cowan, T. Doeppner, D. J. Erb, A. Eychmueller, S. Facsko, R. W. Falcone, L. B. Fletcher, S. Frydrych, G. C. Ganzenmuller, D. O. Gericke, S. H. Glenzer, J. Grenzer, U. Helbig, S. Hiermaier, R. Huebner, A. Laso Garcia, H. J. Lee, M. J. MacDonald, E. E. McBride, P. Neumayer, A. Pak, A. Pelka, I Prencipe, A. Prosvetov, A. Rack, A. Ravasio, R. Redmer, D. Reemts, M. Roedel, M. Schoelmerich, D. Schumacher, M. Tomut, S. J. Turner, A. M. Saunders, P. Sun, J. Vorberger, A. Zettl, D. Kraus
Summary: This study presents the dynamics of free-surface release clouds from compressed polystyrene and pyrolytic graphite, which transform into diamond or lonsdaleite under high pressures. The clouds are released into vacuum or catcher systems and monitored using high-speed recordings. Molecular dynamics simulations provide insights into the preservation rate of diamond during expansion and impact, highlighting the challenges of retrieval. Raman spectroscopy confirms the transformation of compressed polystyrene into graphite, and electron microscopy analysis reveals numerous spherical-like objects on catcher plates, potentially diamonds.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Applied
Runjie Li, Yanyan Zhang, Bing Xing, Mengtian Huang, Ting Wang, Xiaoping Hong, Baocheng Zhou, Benxia Li, Jia Ding, Qi Sui
Summary: The selective oxidation of alcohols using transition-metal-based catalysts is an environmentally friendly approach to produce aldehydes. In this study, mesoporous SBA-15 supported bimetallic NixCoy oxides were synthesized for the catalytic oxidation of alcohols using oxygen as the sole oxidant. The catalytic activity was influenced by the metal composition, with the Ni1Co4/SBA-15 catalyst exhibiting the best performance, achieving a benzyl alcohol conversion of 96.2% and a benzaldehyde selectivity of 98.3%. The results suggest that the electronic structure of the NixCoy/SBA-15 catalysts can be modulated by the Ni/Co ratio, and high Co3+/Co2+ and Ni3+/Ni2+ ratios promote the catalyst activity. The mesoporous structure of SBA-15 support enhances the benzyl alcohol oxidation performance compared to NixCoy nanocatalysts without SBA-15 support.
MICROPOROUS AND MESOPOROUS MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Aditya Sood, Jonah B. Haber, Johan Carlstrom, Elizabeth A. Peterson, Elyse Barre, Johnathan D. Georgaras, Alexander H. M. Reid, Xiaozhe Shen, Marc E. Zajac, Emma C. Regan, Jie Yang, Takashi Taniguchi, Kenji Watanabe, Feng Wang, Xijie Wang, Jeffrey B. Neaton, Tony F. Heinz, Aaron M. Lindenberg, Felipe H. da Jornada, Archana Raja
Summary: In this study, lattice dynamics in photoexcited WSe2/WS2 heterostructures were directly visualized using femtosecond electron diffraction. It was found that both WSe2 and WS2 were heated simultaneously on a picosecond timescale, which cannot be explained by phonon transport across the interface. First-principles calculations revealed a fast channel involving layer-hybridized electronic states, enabling phonon-assisted interlayer transfer of photoexcited electrons. Phonons were emitted in both layers on the femtosecond timescale via this channel, consistent with the simultaneous lattice heating observed experimentally. Strong electron-phonon coupling via layer-hybridized electronic states was identified as a novel route for controlling energy transport across atomic junctions.
NATURE NANOTECHNOLOGY
(2023)
Article
Chemistry, Analytical
Adrian K. Davey, Zhou Li, Natalie Lefton, Branden E. Leonhardt, Alireza Pourghaderi, Stuart McElhany, Derek Popple, Chunhui Dai, Salman Kahn, Matthew N. Dods, Alex Zettl, Carlo Carraro, Roya Maboudian
Summary: An improved colorimetric CO2 sensor (ED/PSP:ZIF-8) is developed by directly incorporating phenol red into the ZIF-8 metal and linker precursor solutions and blending with ethylenediamine. This sensor exhibits enhanced colorimetric gas response compared to the previous one (PSP-ED/ZIF-8) and has high selectivity to CO2 for indoor air quality monitoring. Furthermore, it can operate effectively across a range of humidity.
SENSORS AND ACTUATORS B-CHEMICAL
(2023)
Article
Materials Science, Multidisciplinary
Derek Popple, Mehmet Dogan, Tony Vo Hoang, Scott Stonemeyer, Peter Ercius, Karen C. Bustillo, Marvin Cohen, Alex Zettl
Summary: Nanotube encapsulation is a powerful technique for achieving unconventional solid configurations. Carbon nanotube encapsulation has been used to create ultranarrow and atomically precise HfTe2 nanoribbons, where a transition from a metallic phase to a semiconducting phase was observed. Computational studies were conducted to investigate the effect of charging on the phase transition and the stability of different atomic configurations.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yangjin Lee, Young Woo Choi, Kihyun Lee, Chengyu Song, Peter Ercius, Marvin L. Cohen, Kwanpyo Kim, Alex Zettl
Summary: In this study, one-dimensional (1D) chains of GeX2 (X = S or Se) were reported, and the tetrahedral connectivity was modified at the single-chain limit by precise tuning of the edge-and corner-sharing modes between GeX2 blocks, achieved through diameter-dependent 1D confinement inside a carbon nanotube. Atomic-resolution scanning transmission electron microscopy directly confirmed the existence of two distinct types of GeX2 chains. Density functional theory calculations corroborated the diameter-dependent stability of the system and revealed an intriguing electronic structure that sensitively depended on tetrahedral connectivity and composition.
Article
Multidisciplinary Sciences
Wenyu Zhao, Shaoxin Wang, Sudi Chen, Zuocheng Zhang, Kenji Watanabe, Takashi Taniguchi, Alex Zettl, Feng Wang
Summary: Thermally excited electrons and holes form a quantum-critical Dirac fluid in ultraclean graphene. The electrodynamic responses of this fluid are described by a universal hydrodynamic theory. Researchers observed the presence of a hydrodynamic plasmon and energy wave in ultraclean graphene using on-chip terahertz spectroscopy technique. These findings open up new opportunities to explore collective hydrodynamic excitations in graphene systems.
Article
Physics, Multidisciplinary
Wu Shi, Salman Kahn, Nicolas Leconte, Takashi Taniguchi, Kenji Watanabe, Michael Crommie, Jeil Jung, Alex Zettl
Summary: Recent studies have explored intriguing quantum phenomena in vdW heterostructures and superlattices but mainly focused on the moderate carrier density regime. In this study, we used a newly developed electron beam doping technique to probe high-temperature fractal BZ quantum oscillations in the extreme doping regimes. By accessing ultrahigh electron and hole densities beyond the dielectric breakdown limit, we observed nonmonotonic carrier-density dependence of fractal BZ states and up to fourth-order fractal BZ features. Theoretical simulations explained these findings as a weakening of superlattice effects at high carrier densities.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Chunhui Dai, Derek Popple, Cong Su, Ji-Hoon Park, Kenji Watanabe, Takashi Taniguchi, Jing Kong, Alex Zettl
Summary: The engineering of atomically-precise nanopores in two-dimensional materials holds exciting opportunities for fundamental science studies and various applications. The exceptional stability of hexagonal boron nitride (h-BN) suggests that exposed h-BN nanopores can retain their atomic structure even in gas or liquid environments over time. However, this study discovers that h-BN nanopores undergo dramatic changes in geometry due to atom motion and edge contamination adsorption, even at room temperature.
COMMUNICATIONS CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Haitao Yuan, Xiaoping Hong, Huan Ma, Chunjin Fu, Yudong Guan, Wei Huang, Jingbo Ma, Peng Xia, Min Cao, Liuhai Zheng, Xiaolong Xu, Chengchao Xu, Dongzhou Liu, Zhijie Li, Qingshan Geng, Jigang Wang
Summary: Bacterial infections are common and challenging for diabetic wounds. Nanozymes have the potential to treat bacterial infections, but their low catalytic activity limits their effectiveness. Therefore, it is important to develop novel antibacterial modalities with multiple mechanisms of action.
ACS MATERIALS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Yangjin Lee, Young Woo Choi, Kihyun Lee, Chengyu Song, Peter Ercius, Marvin L. Cohen, Kwanpyo Kim, Alex Zettl
Summary: This paper reports on a family of 1D magnetic van der Waals materials with composition MX3, prepared in fully-isolated fashion within the protective cores of carbon nanotubes. Unique structures different from the well-known 2D honeycomb lattice MX3 structure are identified through atomic-resolution scanning transmission electron microscopy. Density functional theory calculations reveal charge-driven reversible magnetic phase transitions.
ADVANCED MATERIALS
(2023)
