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 Fano‐Majorana Effect and Bound States in the Continuum on a Crossbar‐Shaped Quantum Dot Hybrid Structure

2019 ◽  
pp. 1800498 ◽  
Author(s):  
Juan Pablo Ramos‐Andrade ◽  
David Zambrano ◽  
Pedro A. Orellana
Keyword(s):  
Quantum Dot ◽  
Bound States ◽  
Hybrid Structure ◽  
The Continuum

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

Terahertz Spin-Selective Perfect Absorption Enabled by Quasi-Bound States in the Continuum

2021 ◽  
Author(s):  
zhonglei shen ◽  
Xiangdong Fang ◽  
Shengnan Li ◽  
Wei Yin ◽  
Liuyang Zhang ◽  
...  
Keyword(s):  
Bound States ◽  
Perfect Absorption ◽  
The Continuum

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 Graphene perfect absorber with loss adaptive Q-factor control function enabled by quasi-bound states in the continuum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sangjun Lee ◽  
Joohyung Song ◽  
Sangin Kim
Keyword(s):  
Bound States ◽  
Control Function ◽  
Incident Angle ◽  
Leakage Rate ◽  
Slab Waveguide ◽  
Monolayer Graphene ◽  
Perfect Absorber ◽  
Coupling Condition ◽  
Perfect Absorption ◽  
The Continuum

AbstractNumerous device structures have been proposed for perfect absorption in monolayer graphene under single-sided illumination, all of which requires the critical coupling condition, i.e., the balance between the loss of graphene and the leakage rate of the device. However, due to the difficulty of the precise control of the quality of synthesized graphene and unwanted doping in graphene transferred to the substrate, the loss of graphene is rather unpredictable, so that the perfect absorption is quite difficult to achieve in practice. To solve this problem, we designed a novel perfect absorber structure with a loss adaptive leakage rate control function enabled by the quasi-bound states in the continuum (BIC) and numerically demonstrated its performance. Our designed device is based on a slab-waveguide grating supporting both the quasi-BIC and the guided-mode resonance (GMR); the quasi-BIC with an adjustable leakage rate controlled by an incident angle is responsible for absorption, while the GMR works as an internal mirror. Since the proposed device scheme can have an arbitrarily small leakage rate, it can be used to implement a perfect absorber for any kind of ultrathin absorbing media. Due to the simple structure avoiding an external reflector, the device is easy to fabricate.

scholarly journals Highly Efficient Light Absorption of Monolayer Graphene by Quasi-Bound State in the Continuum

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 484
Author(s):  
Tian Sang ◽  
Sina Abedini Dereshgi ◽  
Wisnu Hadibrata ◽  
Ibrahim Tanriover ◽  
Koray Aydin
Keyword(s):  
Light Absorption ◽  
Near Infrared ◽  
Structural Parameters ◽  
Bound State ◽  
Monolayer Graphene ◽  
Destructive Interference ◽  
Perfect Absorption ◽  
Central Wavelength ◽  
Highly Efficient ◽  
The Continuum

Graphene is an ideal ultrathin material for various optoelectronic devices, but poor light–graphene interaction limits its further applications particularly in the visible (Vis) to near-infrared (NIR) region. Despite tremendous efforts to improve light absorption in graphene, achieving highly efficient light absorption of monolayer graphene within a comparatively simple architecture is still urgently needed. Here, we demonstrate the interesting attribute of bound state in the continuum (BIC) for highly efficient light absorption of graphene by using a simple Si-based photonic crystal slab (PCS) with a slit. Near-perfect absorption of monolayer graphene can be realized due to high confinement of light and near-field enhancement in the Si-based PCS, where BIC turns into quasi-BIC due to the symmetry-breaking of the structure. Theoretical analysis based on the coupled mode theory (CMT) is proposed to evaluate the absorption performances of monolayer graphene integrated with the symmetry-broken PCS, which indicates that high absorption of graphene is feasible at critical coupling based on the destructive interference of transmission light. Moreover, the absorption spectra of the monolayer graphene are stable to the variations of the structural parameters, and the angular tolerances of classical incidence can be effectively improved via full conical incidence. By using the full conical incidence, the angular bandwidths for the peak absorptivity and for the central wavelength of graphene absorption can be enhanced more than five times and 2.92 times, respectively. When the Si-based PCS with graphene is used in refractive index sensors, excellent sensing performances with sensitivity of 604 nm/RIU and figure of merit (FoM) of 151 can be achieved.

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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