scholarly journals Probing the transition from an uncoupled to a strong near-field coupled regime between bright and dark mode resonators in metasurfaces

2014 ◽  
Vol 105 (8) ◽  
pp. 081108 ◽  
Author(s):  
Ranjan Singh ◽  
Ibraheem Al-Naib ◽  
Dibakar Roy Chowdhury ◽  
Longqing Cong ◽  
Carsten Rockstuhl ◽  
...  
Keyword(s):  
Near Field ◽  
Dark Mode

scholarly journals All-dielectric chiral-field-enhanced Raman optical activity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ting-Hui Xiao ◽  
Zhenzhou Cheng ◽  
Zhenyi Luo ◽  
Akihiro Isozaki ◽  
Kotaro Hiramatsu ◽  
...  
Keyword(s):  
Optical Activity ◽  
Metallic Nanoparticles ◽  
Near Field ◽  
Localized Surface Plasmon ◽  
Chiral Field ◽  
Resonance Spectroscopy ◽  
Conformational Structure ◽  
Dark Mode ◽  
Spontaneous Raman Scattering ◽  
Raman Optical Activity

AbstractRaman optical activity (ROA) is effective for studying the conformational structure and behavior of chiral molecules in aqueous solutions and is advantageous over X-ray crystallography and nuclear magnetic resonance spectroscopy in sample preparation and cost performance. However, ROA signals are inherently minuscule; 3–5 orders of magnitude weaker than spontaneous Raman scattering due to the weak chiral light–matter interaction. Localized surface plasmon resonance on metallic nanoparticles has been employed to enhance ROA signals, but suffers from detrimental spectral artifacts due to its photothermal heat generation and inability to efficiently transfer and enhance optical chirality from the far field to the near field. Here we demonstrate all-dielectric chiral-field-enhanced ROA by devising a silicon nanodisk array and exploiting its dark mode to overcome these limitations. Specifically, we use it with pairs of chemical and biological enantiomers to show >100x enhanced chiral light–molecule interaction with negligible artifacts for ROA measurements.

Near-field asymmetries in plasmonic resonators

Nanoscale ◽  
2015 ◽  
Vol 7 (8) ◽  
pp. 3634-3644 ◽  
Author(s):  
Vladimir Aksyuk ◽  
Basudev Lahiri ◽  
Glenn Holland ◽  
Andrea Centrone
Keyword(s):  
Symmetry Breaking ◽  
Near Field ◽  
Dark Mode ◽  
Magnetic Excitations

PTIR reveals symmetry-breaking near-field SEIRA enhancements caused by the interference between electric and magnetic excitations of the resonators’ dark-mode.

scholarly journals Asymmetric excitation of surface plasmons by dark mode coupling

2016 ◽  
Vol 2 (2) ◽  
pp. e1501142 ◽  
Author(s):  
Xueqian Zhang ◽  
Quan Xu ◽  
Quan Li ◽  
Yuehong Xu ◽  
Jianqiang Gu ◽  
...  
Keyword(s):  
Surface Plasmons ◽  
Mode Coupling ◽  
Electromagnetic Waves ◽  
Electromagnetically Induced Transparency ◽  
Near Field ◽  
Coupling Mechanism ◽  
Dark Mode ◽  
Resolution Imaging ◽  
Experimental Findings ◽  
Induced Transparency

Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities.

scholarly journals Dynamically Tunable Resonant Strength in Electromagnetically Induced Transparency (EIT) Analogue by Hybrid Metal-Graphene Metamaterials

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 171 ◽  
Author(s):  
Chaode Lao ◽  
Yaoyao Liang ◽  
Xianjun Wang ◽  
Haihua Fan ◽  
Faqiang Wang ◽  
...  
Keyword(s):  
Optical Networks ◽  
Electromagnetically Induced Transparency ◽  
Near Field ◽  
Monolayer Graphene ◽  
Dark Mode ◽  
Resonance Strength ◽  
Field Coupling ◽  
Terahertz Communications ◽  
Unit Cells ◽  
Induced Transparency

In this paper, a novel method to realize a dynamically tunable analogue of EIT for the resonance strength rather than the resonance frequency is proposed in the terahertz spectrum. The introduced method is composed of a metal EIT-like structure, in which a distinct EIT phenomenon resulting from the near field coupling between bright and dark mode resonators can be obtained, as well as an integrated monolayer graphene ribbon under the dark mode resonator that can continuously adjust the resonance strength of transparency peak by changing the Fermi level of the graphene. Comparing structures that need to be modulated individually for each unit cell of the metamaterials, the proposed modulation mechanism was convenient for achieving synchronous operations for all unit cells. This work demonstrates a new platform of modulating the EIT analogue and paves the way to design terahertz functional devices which meet the needs of optical networks and terahertz communications.

scholarly journals Experimental Demonstration of Electromagnetically Induced Transparency in a Conductively Coupled Flexible Metamaterial with Cheap Aluminum Foil

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Jie Hu ◽  
Tingting Lang ◽  
Weihang Xu ◽  
Jianjun Liu ◽  
Zhi Hong
Keyword(s):  
Electromagnetically Induced Transparency ◽  
Near Field ◽  
Surface Current ◽  
Aluminum Foil ◽  
Ring Resonators ◽  
Dark Mode ◽  
Field Coupling ◽  
New Ideas ◽  
Induced Transparency ◽  
Bright Mode

AbstractWe propose a conductively coupled terahertz metallic metamaterial exhibiting analog of electromagnetically induced transparency (EIT), in which the bright and dark mode antennae interact via surface currents rather than near-field coupling. Aluminum foil, which is very cheap and often used in food package, is used to fabricate our metamaterials. Thus, our metamaterials are also flexible metamaterials. In our design, aluminum bar resonators and aluminum split ring resonators (SRRs) are connected (rather than separated) in the form of a fork-shaped structure. We conduct a numerical simulation and an experiment to analyze the mechanism of the proposed metamaterial. The surface current due to LSP resonance (bright mode) flows along different paths, and a potential difference is generated at the split gaps of the SRRs. Thus, an LC resonance (dark mode) is induced, and the bright mode is suppressed, resulting in EIT. The EIT-like phenomenon exhibited by the metamaterial is induced by surface conducting currents, which may provide new ideas for the design of EIT metamaterials. Moreover, the process of fabricating microstructures on flexible substrates can provide a reference for producing flexible microstructures in the future.

BURIED PLANAR WAVEGUIDE IN KTiOPO4 FORMED BY Cs+ ION EXCHANGE AND Si+ ION IMPLANTATION

2008 ◽  
Vol 22 (10) ◽  
pp. 755-762 ◽  
Author(s):  
RUIFENG ZHANG ◽  
FEI LU ◽  
JIE LIAN ◽  
XIANGZHI LIU ◽  
HANPING LIU ◽  
...  
Keyword(s):  
Refractive Index ◽  
Ion Exchange ◽  
Ion Implantation ◽  
Planar Waveguide ◽  
Near Field ◽  
Refractive Index Profile ◽  
Coupling Method ◽  
Dark Mode ◽  
Field Patterns ◽  
Transport Of Ions

Buried planar waveguide was produced by Cs +– K + ion exchange and Si + ion implantation in z-cut KTiOPO 4 (KTP) single domain crystals. The dark mode spectra of the waveguide were obtained by the prism-coupling method. The refractive index profiles of the Cs +– K + ion exchanged sample were reconstructed using the inverse Wenzel–Kramers–Brillouin (iWKB) method and the analysis of the refractive index profile has shown an exponential distribution in the exchange layer. The Si + ions implanted into the Cs +– K + exchange sample with the energy of 550 keV at a dose of 1.0×1015 ions/cm2 at room temperature to form a buried planar waveguide structure. The program code TRIM'98 (transport of ions in matter) is used to simulate the implantation process. The near field patterns of propagation light in buried waveguide was studied by the end-coupling method.

scholarly journals Analog of multiple electromagnetically induced transparency using double-layered metasurfaces

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Siyuan Liu ◽  
Zhixia Xu ◽  
Xiaoxing Yin ◽  
Hongxin Zhao
Keyword(s):  
Electromagnetically Induced Transparency ◽  
Near Field ◽  
Localized Surface Plasmons ◽  
Dark Mode ◽  
Field Coupling ◽  
Double Peaks ◽  
Resonant Modes ◽  
Physical Essence ◽  
Induced Transparency ◽  
Mode A

Abstract We reported an analog of electromagnetically induced transparency (A-EIT) featured by double transparent peaks in the spectrum. The A-EIT is realized by double-layered metasurface which consists of spoof localized surface plasmons (S-LSP) and cut-wire (CW)-square rings (SR) hybrid. Electric and magnetic S-LSP are excited as bright and dark modes respectively then couple with resonant modes of CW and SR simultaneously to achieve multiple A-EIT. Two bright modes of the electric S-LSP and SR are excited by external electric field directly that produce a bright-bright mode A-EIT. Moreover, the magnetic S-LSP, which cannot be excited by external field directly, is excited through near field coupling from CW, inducing another bright-dark mode A-EIT. Theoretical analysis with corresponding experiment in microwave band are introduced for better insights into physical essence of the double-peaks A-EIT.

Active waveguides by low-fluence carbon implantation in Nd3+-doped fluorophosphate glasses

2016 ◽  
Vol 30 (02) ◽  
pp. 1550266 ◽  
Author(s):  
Chun-Xiao Liu ◽  
Zhe-Yuan Luo ◽  
Yu-Wen Li ◽  
Meng Chen ◽  
Jun Xu ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Semiconductor Industry ◽  
Near Field ◽  
Beam Propagation Method ◽  
Refractive Index Profile ◽  
Propagation Loss ◽  
Dark Mode ◽  
Prism Coupler ◽  
Fluorophosphate Glass ◽  
Implantation Process

A planar waveguide in the Nd[Formula: see text]-doped fluorophosphate glass is fabricated by a 6.0 MeV C[Formula: see text] ion implantation at a low-fluence of [Formula: see text] ions/cm2. The fluence is close to that in semiconductor industry. The dark mode spectra are recorded by a model 2010 prism coupler. The energy losses during the implantation process and the refractive index profile of the waveguide are simulated by the SRIM 2010 code and the reflectivity calculation method (RCM), respectively. The near-field light intensity profile and the propagation loss of the waveguide are measured by an end-face coupling system. The two-dimensional (2D) modal profile of transverse electric (TE) mode for the fabricated waveguide is calculated by the finite difference beam propagation method (FD-BPM). The results of microluminescence and optical absorption reveal that the spectroscopic characteristics of the Nd[Formula: see text]-doped fluorophosphate glass are nearly unaffected by the carbon ion implantation process. This work suggests that the carbon-implanted Nd[Formula: see text]-doped fluorophosphate glass waveguide is a promising candidate for integrated active devices.

Optimization effect of annealing treatment on oxygen-implanted Nd:CNGG waveguides

2016 ◽  
Vol 30 (20) ◽  
pp. 1650261 ◽  
Author(s):  
Chun-Xiao Liu ◽  
Li-Li Fu ◽  
Liang-Liang Cheng ◽  
Xu-Feng Zhu ◽  
She-Bao Lin ◽  
...  
Keyword(s):  
Refractive Index ◽  
Treatment Process ◽  
Near Field ◽  
Annealing Treatment ◽  
Refractive Indices ◽  
Text Line ◽  
Dark Mode ◽  
Oxygen Ion ◽  
Oxygen Ion Implantation ◽  
Better Than

Neodymium-doped calcium niobium gallium garnet (Nd:CNGG) waveguide operated at 632.8 nm is demonstrated by the 3.0-MeV oxygen-ion implantation with a fluence of [Formula: see text] ions/cm2. The annealing treatment at 300[Formula: see text]C for 45 min is carried out to optimize the waveguide quality. The dark-mode spectra are measured by the [Formula: see text]-line technique. The refractive index profiles are calculated from the effective refractive indices of the waveguide modes. The near-field intensity distributions are simulated based on the reconstructed refractive index profiles. The annealing treatment process could effectively remove unwanted defects and optimize the waveguide quality. The optical properties of the annealed waveguide are better than that of the as-implanted waveguide.

scholarly journals Graphene-Modulated Terahertz Metasurfaces for Selective and Active Control of Dual-Band Electromagnetic Induced Reflection (EIR) Windows

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2420
Author(s):  
Xunjun He ◽  
Chenguang Sun ◽  
Yue Wang ◽  
Guangjun Lu ◽  
Jiuxing Jiang ◽  
...  
Keyword(s):  
Active Control ◽  
Slow Light ◽  
Near Field ◽  
Dual Band ◽  
Destructive Interference ◽  
Dark Mode ◽  
Field Coupling ◽  
Control Scheme ◽  
Electrostatic Doping ◽  
Induced Transparency

Currently, metasurfaces (MSs) integrating with different active materials have been widely explored to actively manipulate the resonance intensity of multi-band electromagnetic induced transparency (EIT) windows. Unfortunately, these hybrid MSs can only realize the global control of multi-EIT windows rather than selective control. Here, a graphene-functionalized complementary terahertz MS, composed of a dipole slot and two graphene-integrated quadrupole slots with different sizes, is proposed to execute selective and active control of dual-band electromagnetic induced reflection (EIR) windows. In this structure, dual-band EIR windows arise from the destructive interference caused by the near field coupling between the bright dipole slot and dark quadrupole slot. By embedding graphene ribbons beneath two quadrupole slots, the resonance intensity of two windows can be selectively and actively modulated by adjusting Fermi energy of the corresponding graphene ribbons via electrostatic doping. The theoretical model and field distributions demonstrate that the active tuning behavior can be ascribed to the change in the damper factor of the corresponding dark mode. In addition, the active control of the group delay is further investigated to develop compact slow light devices. Therefore, the selective and active control scheme introduced here can offer new opportunities and platforms for designing multifunctional terahertz devices.

Sign in / Sign up

Export Citation Format

Share Document