Article
Chemistry, Physical
Yujing Ran, Huiping Lu, Shujun Zhao, Qian Guo, Chang Gao, Zhaotan Jiang, Zhi Wang
Summary: Metal nitride NbNx films with different nitrogen content were prepared and demonstrated stoichiometry-tunable on lattice constant, chemical state, and plasmonic properties. The films exhibit dual ENZ behavior in the range of 400 to 1000 nm, with tunable negative real part of epsilon below 1.0. Non-stoichiometric defects, particularly cation vacancies, were found to be key factors affecting the ENZ behavior of NbNx films.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
J. Ryan Nolen, Angela Cleri, Kyle Kelley, Evan L. Runnerstrom, Josh Nordlander, Thomas G. Folland, Jon-Paul Maria, Joshua D. Caldwell
Summary: Doped cadmium oxide films exhibit tunable, low-loss surface plasmon polaritons (SPPs) and epsilon-near-zero (ENZ) modes in the midinfrared range. By manipulating the dielectric environment and spatial overlap of the modes, the SPP-ENZ dispersion can be controlled, leading to applications such as waveguiding, thermal emission, and near-field heat transfer.
ADVANCED PHOTONICS RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Tornike Shubitidze, Wesley A. Britton, Luca Dal Negro
Summary: This study demonstrates experimentally the enhancement of the nonlinear refractive index variation of 30 nm-thick indium tin oxide (ITO) nanolayers coupled to Tamm plasmon-polariton states. The linear and nonlinear optical properties of ITO materials and photonic structures are investigated using spectroscopic ellipsometry and intensity-dependent Z-scan nonlinear characterization, showing a refractive index variation of Delta n approximately 2 in the low excitation regime.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Hang Jiang, Yuanan Zhao, Hao Ma, Yi Wu, Meiling Chen, Mengxia Wang, Weili Zhang, Yujie Peng, Yuxin Leng, Zhaoliang Cao, Jianda Shao
Summary: An ultrafast all-optical switch based on enhanced nonlinear absorption of corrugated indium tin oxide (ITO) thin films is proposed. The switch achieves broad-band, polarization-independent, and wide-angle characteristics by taking advantage of the perfect absorption and localized field enhancement of epsilon-near-zero and localized surface plasmon resonance modes.
Article
Chemistry, Multidisciplinary
Xueli Wang, Kaili Chang, Weitao Liu, Hongqin Wang, Junying Chen, Kaihui Liu, Jianing Chen, Ke Chen
Summary: In this study, an effective strategy for tunable topological transitions in mid-infrared hyperbolic vdW metasurfaces (HMSs) is proposed via enhanced plasmon-phonon polaritons coupling. The metasurfaces are composed of in-plane heterostructures of thin-layer h-BN and monolayer graphene strips (iHBNG) as meta-atoms. The graphene-plasmon-enhanced near-field coupling enables a large tunability of light fields without frequency shift, involving topological transitions of polaritonic modes, unidirectional polariton propagation, and local-density-of-state enhancement.
Article
Materials Science, Multidisciplinary
Dipa Ghindani, Alireza R. Rashed, Mohsin Habib, Humeyra Caglayan
Summary: This work demonstrates the active tuning of coupling strength in a strongly coupled system comprised of a thin epsilon-near-zero material and gold nanorods. A novel gating scheme using an ionic liquid is developed to bias the system and tune the coupling in transmission mode, resulting in a significant tuning of the coupled resonance up to 30 nm by changing bias voltages from 0 to 4.5 V. This control mechanism on strong coupling offers exciting opportunities for various disruptive applications by providing advanced control and tunability.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Khant Minn, Aleksei Anopchenko, Ching-Wen Chang, Ragini Mishra, Jinmin Kim, Zhenrong Zhang, Yu-Jung Lu, Shangjr Gwo, Ho Wai Howard Lee
Summary: Room-temperature photoluminescence enhancement of molybdenum disulfide monolayers on epitaxial titanium nitride thin films is observed, with stronger enhancement as titanium nitride becomes more metallic, especially at excitation wavelengths equal to or longer than the titanium nitride's epsilon-near-zero (ENZ) wavelength. The enhancement is attributed to increased excitation field in molybdenum disulfide at titanium nitride's ENZ wavelength and interference effects for thick spacers that separate molybdenum disulfide flakes from titanium nitride films in the metallic regime.
Article
Optics
Jiaye Wu, Xuanyi Liu, Boris A. Malomed, Kuan-Chang Chang, Minghe Zhao, Kang Qi, Yanhua Sha, Ze Tao Xie, Marco Clementi, Camille-Sophie Bres, Shengdong Zhang, Hongyan Fu, Qian Li
Summary: This study reports on a novel photonic system that emulates the scheme of a radio-frequency superconducting quantum interference device (RF-SQUID) using epsilon-near-zero (ENZ) nanolayers in a fiber laser cavity. Different ENZ wavelengths lead to distinct spectral outputs through the variation of cavity resonances. The findings provide insights into ultrafast ENZ photonics, enabling the design of nanophotonic on-chip devices and the study of superconducting and quantum-mechanical systems.
LASER & PHOTONICS REVIEWS
(2022)
Article
Nanoscience & Nanotechnology
Saumya Choudhary, Saleem Iqbal, Mohammad Karimi, Orad Reshef, M. Zahirul Alam, Robert W. Boyd
Summary: Researchers propose a strongly coupled bilayered structure consisting of a thin gold film on a thin indium tin oxide (ITO) film, which supports hybrid polariton modes with both propagation lengths and mode confinement advantages. This structure is useful for active tuning of strong coupling, ultrafast switching, and enhanced nonlinear interactions at near-infrared frequencies.
Article
Materials Science, Multidisciplinary
Kenji Ikeda, Tianji Liu, Yasutomo Ota, Nobukiyo Kobayashi, Satoshi Iwamoto
Summary: This study demonstrates the enhanced magneto-optical effects in pristine indium tin oxide (ITO) materials with near-zero permittivity properties at telecommunication wavelengths. The results show that the intrinsic properties of ITO materials lead to the enhancement of magneto-optical rotation, and this mechanism can be applied to various near-zero permittivity materials, including those incorporating ferromagnetic materials, expanding the opportunities for the development of nanophotonic devices.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Jing Huang, Jianqi Li, Yunchang Xiao, Jianying Li
Summary: We investigated the broadband optical nonlinearity of indium tin oxide (ITO) films with different thickness in the near-infrared spectrum region. The maximum nonlinear response was observed at the epsilon-near-zero (ENZ) wavelength, with the nonlinear refractive index and absorption coefficient significantly higher than at the 1000 nm wavelength. The large modulation depth and numerical simulation analysis highlight the potential applications of ITO in nonlinear optics and all-optical modulators.
Article
Chemistry, Physical
Ryan Bower, Matthew P. Wells, Freya Johnson, Rebecca Kilmurray, Brock Doiron, Eleonora Cali, Giuseppe Mallia, Bin Zou, Andrei P. Mihai, Nicholas M. Harrison, Sarah Fearn, Rupert Oulton, Neil McN. Alford, Lesley F. Cohen, Peter K. Petrov
Summary: This study investigates the optical response and electrical properties of reactively sputtered niobium oxynitride thin films through experimental and computational simulations. The experimental results show that these films have screened plasma wavelengths tunable over a range of 90 nm, and exhibit a double epsilon-near-zero behavior. This behavior is attributed to the incorporation of oxygen into the films during deposition.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Shu-qi Wu, Hao-yuan Song, Yu-bo Li, Shu-fang Fu, Xuan-zhang Wang
Summary: We present a tunable spin Hall effect of light (SHEL) by introducing a monolayer of graphene on hBN, and discuss the influence of different factors on this effect. These findings may lead to potential applications in nano-optical devices.
RESULTS IN PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Kyu-Ri Choi, Minjae Kim, Jeong Weon Wu, Anthony D'Aleo, Yeon Ui Lee
Summary: Researchers have achieved enhanced directionality of photoluminescence emission by placing an organic dielectric film on top of a polymeric fluorophore film. The directive emission is increased by 42% by utilizing the structural coherence in the polymeric fluorophore film and the epsilon-near-zero response in the organic dielectric film. This capability to control directive emission with organic dielectric films is highly useful in applications requiring bio-compatibility of a fluorophore-embedding medium.
Article
Physics, Multidisciplinary
Heng Wang, Lixun Sun, Kang Du, Wending Zhang, SooJin Chua, Guixin Li, Ting Mei
Summary: This paper proposes a theoretical concept to explain the total energy of conduction electrons exceeding their thermal equilibrium value. The time-varying thermal energy is used to describe the transient optical response of typical ENZ material ITO, and the response to optical excitation is experimentally verified.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Materials Science, Multidisciplinary
Zhewei Wang, Chaonan Chen, Ke Wu, Haining Chong, Hui Ye
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2019)
Article
Nanoscience & Nanotechnology
Haining Chong, Zemin Xu, Zhewei Wang, Jianbo Yu, Tobias Biesner, Martin Dressel, Lan Wu, Qiang Li, Hui Ye
ACS APPLIED MATERIALS & INTERFACES
(2019)
Article
Optics
Ke Wu, Zhewei Wang, Jianhan Yang, Hui Ye
Article
Nanoscience & Nanotechnology
Jianhan Yang, Hossam A. Almossalami, Zhewei Wang, Ke Wu, Chen Wang, Kuan Sun, Yang Michael Yang, Hui Ye
ACS APPLIED MATERIALS & INTERFACES
(2019)
Article
Optics
Zhewei Wang, Haining Chong, Jianhan Yang, Hui Ye
Article
Nanoscience & Nanotechnology
Ka Kin Lam, Sheung Mei Ng, Hon Fai Wong, Linfeng Fei, Yukuai Liu, Ka Ho Chan, Hui Ye, Chi Wah Leung, Chee Leung Mak
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Physics, Applied
Jun Zheng, Hossam A. Almossalami, Kuanan Chen, Xinlan Yu, Hui Ye
Summary: Plasmonic materials are used in various fields due to their unique optical properties, and researchers often need detailed permittivity behavior near surface plasmons' excitation wavelengths. This study introduces a spectral fitting method to quickly obtain materials' permittivity at ENZ region, providing specific data and theoretical support for researchers in the field of photoelectric properties of plasmonic materials.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Shuguang Wang, Zhenghu Zuo, Zhenghui Ji, Xiaorui Chen, Hui Ye, Guchang Han
Summary: Damage mechanisms induced by ion beam etching (IBE) process in the fabrication of magnetic tunnel junctions (MTJs) were studied, resulting in the formation of an amorphous shell with low conductivity and tunneling magnetoresistance (TMR). Optimizing the IBE process reduced TMR loss ratio and increased coercive field (Hc) for the same MTJ stack.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2021)
Article
Optics
Hossam A. Almossalami, Jun Zheng, Qili Hu, Sen Liang, Kuan-An Chen, Hui Ye
Summary: The study investigates sub-bandgap light absorption in germanium films through Berreman mode and its enhancement by weak coupling to Fabry-Perot cavity mode. By integrating the semiconductor film into a microcavity structure and tuning its resonance frequency, significant light absorption at large incidence angles can be achieved, providing a novel and simple method to enhance the optical and optoelectronic responses of any ENZ material.
Article
Materials Science, Multidisciplinary
Hossam A. Almossalami, Sen Liang, Jun Zheng, Hui Ye
Summary: This paper designs and fabricates absorptive metamaterials composed of antimony-doped-germanium and germanium films with different epsilon-near-zero wavelengths, achieving broadband perfect light absorption around the epsilon-near-zero wavelengths.
OPTICAL MATERIALS EXPRESS
(2022)
Article
Optics
Xinlan Yu, Jiahuan Qiu, Qili Hu, Kuanan Chen, Jun Zheng, Sen Liang, Miao Du, Hui Ye
Summary: In this paper, we investigate the wide tuning of Epsilon-near-zero (ENZ) wavelength in the near-infrared region using a modified PEDOT:PSS film formed with a Metastable liquid-liquid Contact (MLLC) solution treatment method. We also demonstrate a tunable polarization absorber by exciting the Berreman mode through a simple structural design.
Article
Optics
Haining Chong, Yuanhao Mu, Hui Ye, Yangjian Cai
Summary: We have experimentally and theoretically demonstrated a mid-infrared perfect absorber using all group-IV epitaxial layered composite structures. The absorber achieves multispectral narrowband strong absorption, attributed to the combined effects of asymmetric Fabry-Perot interference and plasmonic resonance in the subwavelength-patterned metal-dielectric-metal stack. The absorption resonance is analyzed by reflection and transmission, with the localized plasmon resonance in the dual-metal region modulated by the horizontal and vertical profile, while the asymmetric FP modes are modulated only by the vertical geometric parameters. The strong coupling between modes is shown in semi-empirical calculations, with a large Rabi-splitting energy reaching 46% of the mean energy of the plasmonic mode under proper horizontal profile. A wavelength-adjustable all-group-IV-semiconductor plasmonic perfect absorber holds potential for photonic-electronic integration.
Article
Materials Science, Multidisciplinary
Kuan-An Chen, Sen Liang, Jun Zheng, Chengcan Han, Yueguang Zhang, Lei Lin, Hui Ye
Summary: The optical performances of gallium-doped zinc oxide (GZO) material with an epsilon near zero (ENZ) can be adjusted by altering the substrate types, heating temperatures, and post-annealing procedures. Four GZO film samples with different imaginary parts of permittivity (ε′′) at their ENZ wavelengths were deposited using radio frequency magnetron sputtering technology and showed perfect absorption at specific incident angles and wavelengths. Smaller εENZ values of the GZO film result in a narrower bandwidth for near perfect absorption peak, while larger εENZ values lead to a broader bandwidth. The incident angle required for perfect absorption is also affected by the εENZ values of the GZO films. To achieve near perfect absorption, larger εENZ values provide a wider window, while smaller εENZ values make it easier to achieve perfect absorption.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Nanoscience & Nanotechnology
Qili Hu, Xinlan Yu, Hongqi Liu, Jiahuan Qiu, Wei Tang, Sen Liang, Linjun Li, Miao Du, Junjun Jia, Hui Ye
Summary: Epsilon-near-zero (ENZ) materials, such as EG-modified PEDOT films, have shown enhanced optical nonlinearity and can be used in various applications. These films exhibit ENZ wavelengths from mid-infrared to visible regimes, with the nonlinearity coefficients surpassing those of most inorganic ENZ materials. The enhancement is attributed to the increased absorptance of bipolarons within the PEDOT films, leading to a significant change in transmittance between low and high power intensities. This highly tunable material has potential applications in plasmonics, nonlinear optics, and on-chip nanophotonic devices.
