scholarly journals Bound States in the Continuum in All‐Dielectric Metasurface: Separation of Sub‐10 nm Enantiomers

2021 ◽  
pp. 2100280
Author(s):  
Libang Mao ◽  
Kuan Liu ◽  
Meng Lian ◽  
Jingyuan Jia ◽  
Ying Su ◽  
...  
Keyword(s):  
Bound States ◽  
Dielectric Metasurface ◽  
The Continuum

scholarly journals Bound states in the continuum-induced enhancement of evanescent field confinement

2021 ◽  
Vol 2015 (1) ◽  
pp. 012083
Author(s):  
S I Lepeshov ◽  
A A Bogdanov
Keyword(s):  
Electric Field ◽  
Bound States ◽  
Field Enhancement ◽  
Fold Increase ◽  
Evanescent Waves ◽  
Electric Field Enhancement ◽  
Light Line ◽  
Field Localization ◽  
Dielectric Metasurface ◽  
The Continuum

Abstract Here, the enhancement of electromagnetic field confinement in an all-dielectric metasurface is demonstrated. The enhanced confinement is achieved when the polarization singularity, corresponding to accidental bound states in the continuum, moves to the domain of evanescent fields (under the light line). Such a hybridization of the bound states and evanescent waves results in the 70-fold increase of the electric field enhancement on the top of the metasurface and boosting of the electric field localization.

High Q-Factor All-Dielectric Metasurface Based on Bound States in the Continuum

2019 ◽  
Author(s):  
Shaimaa I. Azzam ◽  
Krishnakali Chaudhuri ◽  
Vladimir M. Shalaev ◽  
Alexandra Boltasseva ◽  
Alexander V. Kildishev
Keyword(s):  
Bound States ◽  
Q Factor ◽  
High Q ◽  
Dielectric Metasurface ◽  
The Continuum

scholarly journals Ultrasensitive terahertz sensing with high-Q toroidal dipole resonance governed by bound states in the continuum in all-dielectric metasurface

Nanophotonics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 1295-1307
Author(s):  
Yulin Wang ◽  
Zhanghua Han ◽  
Yong Du ◽  
Jianyuan Qin
Keyword(s):  
Bound States ◽  
Photonic Devices ◽  
Low Loss ◽  
Photonic Sensor ◽  
Dipole Resonance ◽  
Ultrahigh Sensitivity ◽  
Terahertz Frequencies ◽  
Symmetry Protected ◽  
Dielectric Metasurface ◽  
The Continuum

Abstract Toroidal dipole (TD) with weak coupling to the electromagnetic fields offers tremendous potential for advanced design of photonic devices. However, the excitation of high quality (Q) factor TD resonances in these devices is challenging. Here, we investigate ultrahigh-Q factor TD resonances at terahertz frequencies arising from a distortion of symmetry-protected bound states in the continuum (BIC) in all-dielectric metasurface consisting of an array of high-index tetramer clusters. By elaborately arranging the cylinders forming an asymmetric cluster, two distinct TD resonances governed by BIC are excited and identified. One is distinguished as intracluster TD mode that occurs in the interior of tetramer cluster, and the other one is intercluster TD mode that arises from the two neighboring clusters. Such TD resonances can be turned into ultrahigh-Q leaky resonances by controlling the asymmetry of cluster. The low-loss TD resonances with extremely narrow linewidth are very sensitive to the change in the refractive index of the surrounding media, achieving ultrahigh sensitivity level of 489 GHz/RIU. These findings will open up an avenue to develop ultrasensitive photonic sensor in the terahertz regime.

scholarly journals A Bifunctional Silicon Dielectric Metasurface Based on Quasi-Bound States in the Continuum

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2357
Author(s):  
Jianan Wang ◽  
Weici Liu ◽  
Zhongchao Wei ◽  
Hongyun Meng ◽  
Hongzhan Liu ◽  
...  
Keyword(s):  
Bound States ◽  
Polarized Light ◽  
Parameter Tuning ◽  
Optical Devices ◽  
Low Loss ◽  
High Quality ◽  
Unit Structure ◽  
Incident Plane ◽  
Dielectric Metasurface ◽  
The Continuum

Quasi-bound states in the continuum provide an effective and observable way to improve metasurface performance, usually with an ultra-high-quality factor. Dielectric metasurfaces dependent on Mie resonances have the characteristic of significantly low loss, and the polarization can be affected by the parameter tuning of the structure. Based on the theory of quasi-bound states in the continuum, we propose and simulate a bifunctional resonant metasurface, whose periodic unit structure consists of four antiparallel and symmetrical amorphous silicon columns embedded in a poly(methyl methacrylate) layer. The metasurface can exhibit an extreme Huygens’ regime in the case of an incident plane wave with linear polarization, while exhibiting chirality in the case of incident circular polarized light. Our structure provides ideas for promoting the multifunctional development of flat optical devices, as well as presenting potential in polarization-dependent fields.

Bound states in the continuum in double-hole array perforated in a layer of photonic crystal slab

2019 ◽  
Vol 12 (12) ◽  
pp. 125002 ◽  
Author(s):  
Suxia Xie ◽  
Changzhong Xie ◽  
Song Xie ◽  
Jie Zhan ◽  
Zhijian Li ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Bound States ◽  
Hole Array ◽  
Photonic Crystal Slab ◽  
The Continuum

scholarly journals Differentiating and quantifying exosome secretion from a single cell using quasi-bound states in the continuum

Nanophotonics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1081-1086 ◽  
Author(s):  
Abdoulaye Ndao ◽  
Liyi Hsu ◽  
Wei Cai ◽  
Jeongho Ha ◽  
Junhee Park ◽  
...  
Keyword(s):  
Single Cell ◽  
Optical Sensors ◽  
Figure Of Merit ◽  
Bound States ◽  
Single Cell Analysis ◽  
Optical Cavity ◽  
High Sensitivity ◽  
Cell Secretion ◽  
The Continuum ◽  
Refractive Index Detection

AbstractOne of the key challenges in biology is to understand how individual cells process information and respond to perturbations. However, most of the existing single-cell analysis methods can only provide a glimpse of cell properties at specific time points and are unable to provide cell secretion and protein analysis at single-cell resolution. To address the limits of existing methods and to accelerate discoveries from single-cell studies, we propose and experimentally demonstrate a new sensor based on bound states in the continuum to quantify exosome secretion from a single cell. Our optical sensors demonstrate high-sensitivity refractive index detection. Because of the strong overlap between the medium supporting the mode and the analytes, such an optical cavity has a figure of merit of 677 and sensitivity of 440 nm/RIU. Such results facilitate technological progress for highly conducive optical sensors for different biomedical applications.

scholarly journals Plasmonic hot-electron photodetection with quasi-bound states in the continuum and guided resonances

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenhao Wang ◽  
Lucas V. Besteiro ◽  
Peng Yu ◽  
Feng Lin ◽  
Alexander O. Govorov ◽  
...  
Keyword(s):  
Bound States ◽  
Structural Parameters ◽  
Hybrid Structure ◽  
Fine Tuning ◽  
Hot Electrons ◽  
Hot Electron ◽  
Perfect Absorption ◽  
High Loss ◽  
Guided Mode ◽  
The Continuum

Abstract Hot electrons generated in metallic nanostructures have shown promising perspectives for photodetection. This has prompted efforts to enhance the absorption of photons by metals. However, most strategies require fine-tuning of the geometric parameters to achieve perfect absorption, accompanied by the demanding fabrications. Here, we theoretically propose a Ag grating/TiO2 cladding hybrid structure for hot electron photodetection (HEPD) by combining quasi-bound states in the continuum (BIC) and plasmonic hot electrons. Enabled by quasi-BIC, perfect absorption can be readily achieved and it is robust against the change of several structural parameters due to the topological nature of BIC. Also, we show that the guided mode can be folded into the light cone by introducing a disturbance to become a guided resonance, which then gives rise to a narrow-band HEPD that is difficult to be achieved in the high loss gold plasmonics. Combining the quasi-BIC and the guided resonance, we also realize a multiband HEPD with near-perfect absorption. Our work suggests new routes to enhance the light-harvesting in plasmonic nanosystems.

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