scholarly journals Bound states in the continuum (BIC) accompanied by avoided crossings in leaky-mode photonic lattices

Nanophotonics ◽  
2020 ◽  
Vol 9 (14) ◽  
pp. 4373-4380 ◽  
Author(s):  
Sun-Goo Lee ◽  
Seong-Han Kim ◽  
Chul-Sik Kee
Keyword(s):  
Mirror Symmetry ◽  
Bound States ◽  
Radiation Power ◽  
Leaky Mode ◽  
Slab Geometry ◽  
Photonic Lattices ◽  
Guided Mode ◽  
Avoided Crossing ◽  
Avoided Crossings ◽  
The Continuum

AbstractWhen two nonorthogonal resonances are coupled to the same radiation channel, avoided crossing arises and a bound state in the continuum (BIC) appears with appropriate conditions in parametric space. This paper presents numerical and analytical results on the properties of avoided crossing and BIC due to the coupled guided-mode resonances in one-dimensional (1D) leaky-mode photonic lattices with slab geometry. In symmetric photonic lattices with up-down mirror symmetry, Friedrich–Wintgen BICs with infinite lifetime are accompanied by avoided crossings due to the coupling between two guided modes with the same transverse parity. In asymmetric photonic lattices with broken up-down mirror symmetry, quasi-BICs with finite lifetime appear with avoided crossings because radiating waves from different modes cannot be completely eliminated. We also show that unidirectional-BICs are accompanied by avoided crossings due to guided-mode resonances with different transverse parities in asymmetric photonic lattices. The Q factor of a unidirectional-BIC is finite, but its radiation power in the upward or downward direction is significantly smaller than that in the opposite direction. Our results may be helpful in engineering BICs and avoided crossings in diverse photonic systems that support leaky modes.

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.

scholarly journals Coupled-wave formalism for bound states in the continuum in guided-mode resonant gratings

2019 ◽  
Vol 99 (6) ◽  
Author(s):  
Dmitry A. Bykov ◽  
Evgeni A. Bezus ◽  
Leonid L. Doskolovich
Keyword(s):  
Bound States ◽  
Guided Mode ◽  
The Continuum ◽  
Coupled Wave

scholarly journals Bound states in the continuum in strong-coupling and weak-coupling regimes under the cylinder – ring transition

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nikolay Solodovchenko ◽  
Kirill Samusev ◽  
Daria Bochek ◽  
Mikhail Limonov
Keyword(s):  
Strong Coupling ◽  
Weak Coupling ◽  
Bound States ◽  
Dielectric Cylinder ◽  
Weak Coupling Regime ◽  
Field Zone ◽  
The Past ◽  
Resonant Modes ◽  
Avoided Crossing ◽  
The Continuum

Abstract Bound states in the continuum (BIC) have been at the forefront of research in optics and photonics over the past decade. It is of great interest to study the effects associated with quasi-BICs in the simplest structures, where quasi-BICs are very pronounced. An example is a dielectric cylinder, and in a number of works, quasi-BICs have been studied both in single cylinders and in structures composed of cylinders. In this work, we studied the properties of quasi-BICs during the transition from a homogeneous dielectric cylinder in an air environment to a ring with narrow walls while increasing the diameter of the inner air cylinder gradually. The results demonstrate the quasi-BIC crossover from the strong-coupling to the weak-coupling regime, which manifests itself in the transition from the avoided crossing of branches to their intersection with the quasi-BIC being preserved on only one straight branch. In the regime of strong-coupling and quasi-BIC, three waves interfere in the far-field zone: two waves corresponding to the resonant modes of the structure and the wave scattered by the structure as a whole. The validity of the Fano resonance concept is discussed since it describes the interference of only two waves under weak coupling conditions.

scholarly journals Sound trapping in an open resonator

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lujun Huang ◽  
Yan Kei Chiang ◽  
Sibo Huang ◽  
Chen Shen ◽  
Fu Deng ◽  
...  
Keyword(s):  
Quality Factor ◽  
Mirror Symmetry ◽  
Bound States ◽  
Open Resonator ◽  
Acoustic Resonator ◽  
High Quality Factor ◽  
High Quality ◽  
Order Of Magnitude ◽  
Symmetry Protected ◽  
The Continuum

AbstractThe ability of sound energy confinement with high-quality factor resonance is of vital importance for acoustic devices requiring high intensity and hypersensitivity in biological ultrasonics, enhanced collimated sound emission (i.e. sound laser) and high-resolution sensing. However, structures reported so far have been experimentally demonstrated with a limited quality factor of acoustic resonances, up to several tens in an open resonator. The emergence of bound states in the continuum makes it possible to realize high quality factor acoustic modes. Here, we report the theoretical design and experimental demonstration of acoustic bound states in the continuum supported by a single open resonator. We predicted that such an open acoustic resonator could simultaneously support three types of bound states in the continuum, including symmetry protected bound states in the continuum, Friedrich-Wintgen bound states in the continuum induced by mode interference, as well as a new type-mirror symmetry induced bound states in the continuum. We also experimentally demonstrated their existence with quality factor up to one order of magnitude greater than the highest quality factor reported in an open resonator.

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.

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