Plasmonic nanosensor based on sharp Fano resonances induced by aperture-coupled slot system

A novel refractive index nanosensor with compound structures is proposed in this paper. It consists of three different kinds of resonators and two stubs which are side-coupled to a metal–dielectric–metal (MDM) waveguide. By utilizing numerical investigation with the finite element method (FEM), the simulation results show that the transmission spectrum of the nanosensor has as many as five sharp Fano resonance peaks. Due to their different resonance mechanisms, each resonance peak can be independently tuned by adjusting the corresponding parameters of the structure. In addition, the sensitivity of the nanosensor is found to be up to 1900 nm/RIU. For practical application, a legitimate combination of various different components, such as T-shaped, ring, and split-ring cavities, has been proposed which dramatically reduces the nanosensor dimensions without sacrificing performance. These design concepts pave the way for the construction of compact on-chip plasmonic structures, which can be widely applied to nanosensors, optical splitters, filters, optical switches, nonlinear photonic and slow-light devices.

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High-Resolution Photoabsorption Spectrum of Cs+ (5p61So + 5p5ns, nd) Between 504A and 600A using a Laser Ionized Cs Vapor Column

International Astronomical Union Colloquium ◽

10.1017/s0252921100085481 ◽

1984 ◽

Vol 86 ◽

pp. 124-124

Author(s):

T.J. McIlrath ◽

V. Kaufman ◽

J. Sugar ◽

W.T. Hill ◽

D. Cooper

Keyword(s):

High Resolution ◽

Laser Pulse ◽

High Voltage ◽

Power Output ◽

Random Phase ◽

Grazing Incidence ◽

Fano Resonances ◽

Line Shapes ◽

Phase Calculation ◽

Photoabsorption Spectrum

Rapid ionization of Cs vapor in a heat pipe at 0.05 torr was achieved by pumping the 6s 2S½ – 7p 2P½ transition (f=0.007)1 with a flash-pumped dye laser at 4593.2A and I MW power output. Photoabsorptian initiated at the end of the laser pulse(≃ 0.5/s) showed the 5p5ns and nd series below and above the 5p52P3/2 threshold at 535.4A. Broad Beutler - Fano resonances appeared in the d series above threshold. The spectrum was recorded photographically on a 10.7m grazing incidence spectrograph using a continuum background generated by a BRV high-voltage spark source with a uranium anode. We will compare the line-shapes and the quantum defect (Lu-Fano2) plot with the predictions of a relativistic random phase calculation.

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Active nonlocal metasurfaces

Nanophotonics ◽

10.1515/nanoph-2020-0375 ◽

2020 ◽

Vol 10 (1) ◽

pp. 655-665

Author(s):

Stephanie C. Malek ◽

Adam C. Overvig ◽

Sajan Shrestha ◽

Nanfang Yu

Keyword(s):

Bound States ◽

Fano Resonances ◽

Spatial Control ◽

Technical Challenge ◽

Materials Engineering ◽

Narrow Bandwidth ◽

Wavefront Shaping ◽

Mechanical Stretching ◽

Proof Of Principle ◽

The Continuum

AbstractActively tunable and reconfigurable wavefront shaping by optical metasurfaces poses a significant technical challenge often requiring unconventional materials engineering and nanofabrication. Most wavefront-shaping metasurfaces can be considered “local” in that their operation depends on the responses of individual meta-units. In contrast, “nonlocal” metasurfaces function based on the modes supported by many adjacent meta-units, resulting in sharp spectral features but typically no spatial control of the outgoing wavefront. Recently, nonlocal metasurfaces based on quasi-bound states in the continuum have been shown to produce designer wavefronts only across the narrow bandwidth of the supported Fano resonance. Here, we leverage the enhanced light-matter interactions associated with sharp Fano resonances to explore the active modulation of optical spectra and wavefronts by refractive-index tuning and mechanical stretching. We experimentally demonstrate proof-of-principle thermo-optically tuned nonlocal metasurfaces made of silicon and numerically demonstrate nonlocal metasurfaces that thermo-optically switch between distinct wavefront shapes. This meta-optics platform for thermally reconfigurable wavefront shaping requires neither unusual materials and fabrication nor active control of individual meta-units.

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Graphene–polyimide-integrated metasurface for ultrasensitive modulation of higher-order terahertz fano resonances at the Dirac point

Applied Surface Science ◽

10.1016/j.apsusc.2021.150182 ◽

2021 ◽

pp. 150182

Author(s):

Maosheng Yang ◽

Tengteng Li ◽

Ju Gao ◽

Xin Yan ◽

Lanju Liang ◽

...

Keyword(s):

Dirac Point ◽

Higher Order ◽

Fano Resonances

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Tailoring exceptional points in a hybrid PT-symmetric and anti-PT-symmetric scattering system

Nanophotonics ◽

10.1515/nanoph-2021-0245 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Zhicheng Xiao ◽

Andrea Alù

Keyword(s):

High Resolution ◽

Real Time ◽

Quantum Systems ◽

Symmetric System ◽

Microwave Circuit ◽

High Resolution Imaging ◽

Fano Resonances ◽

Real Time Control ◽

Time Control ◽

Resolution Imaging

Abstract Fano resonances feature an asymmetric lineshape with controllable linewidth, stemming from the interplay between bright and dark resonances. They provide efficient opportunities to shape the scattering lineshape, but they usually lack flexibility and tunability and are hindered by loss in passive systems. Here, we explore a hybrid parity-time (PT) and anti-parity-time (APT) symmetric system supporting unitary scattering features with highly tunable Fano resonances. The PT-APT-symmetric system can be envisioned in nanophotonic and microwave circuit implementations, allowing for real-time control of the scattering lineshape and its underlying singularities. Our study shows the opportunities enabled by non-Hermitian platforms to control scattering lineshapes for a plethora of photonic, electronic, and quantum systems, with potential for high-resolution imaging, switching, sensing, and multiplexing.

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High Sensitivity Plasmonic Sensor Based on Fano Resonance with Inverted U-Shaped Resonator

Sensors ◽

10.3390/s21041164 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1164

Author(s):

Gongli Xiao ◽

Yanping Xu ◽

Hongyan Yang ◽

Zetao Ou ◽

Jianyun Chen ◽

...

Keyword(s):

Fano Resonance ◽

Figure Of Merit ◽

High Sensitivity ◽

Refractive Index Sensor ◽

Multimode Interference ◽

Geometrical Parameters ◽

The Finite Element Method ◽

Plasmonic Sensor ◽

Coupled Mode ◽

Plasmonic Nanosensor

Herein, we propose a tunable plasmonic sensor with Fano resonators in an inverted U-shaped resonator. By manipulating the sharp asymmetric Fano resonance peaks, a high-sensitivity refractive index sensor can be realized. Using the multimode interference coupled-mode theory and the finite element method, we numerically simulate the influences of geometrical parameters on the plasmonic sensor. Optimizing the structure parameters, we can achieve a high plasmonic sensor with the maximum sensitivity for 840 nm/RIUand figure of merit for 3.9 × 105. The research results provide a reliable theoretical basis for designing high sensitivity to the next generation plasmonic nanosensor.

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