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.

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 Hybrid Nanodisk Film for Ultra-Narrowband Filtering, Near-Perfect Absorption and Wide Range Sensing

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 334 ◽  
Author(s):  
Wenli Cui ◽  
Wei Peng ◽  
Li Yu ◽  
Xiaolin Luo ◽  
Huixuan Gao ◽  
...  
Keyword(s):  
Plasmon Resonance ◽  
High Performance ◽  
Near Infrared ◽  
Structural Parameters ◽  
Normal Incidence ◽  
Plasmonic Nanostructures ◽  
Perfect Absorption ◽  
Biomedical Sensing ◽  
Wide Range ◽  
Plasmon Resonances

The miniaturization and integration of photonic devices are new requirements in the novel optics field due to the development of photonic information technology. In this paper, we report that a multifunctional layered structure of Au, SiO2 and hexagonal nanodisk film is advantageous for ultra-narrowband filtering, near-perfect absorption and sensing in a wide refractive index (RI) region. This hexagonal nanostructure presented two remarkable polarization independent plasmon resonances with near-zero reflectivity and near-perfect absorptivity under normal incidence in the visible and near-infrared spectral ranges. The narrowest full width at half maximum (FWHM) of these resonances was predicted to be excellent at 5 nm. More notably, the double plasmon resonances showed extremely obvious differences in RI responses. For the first plasmon resonance, an evident linear redshift was observed in a wide RI range from 1.00 to 1.40, and a high RI sensitivity of 600 nm/RIU was obtained compared to other plasmonic nanostructures, such as square and honeycomb-like nanostructures. For the second plasmon resonance with excellent FWHM at 946 nm, its wavelength position almost remained unmovable in the case of changing RI surrounding nanodisks in the same regime. Most unusually, its resonant wavelength was insensitive to nearly all structural parameters except the structural period. The underlying physical mechanism was analyzed in detail for double plasmon resonances. This work was significant in developing high-performance integrated optical devices for filtering, absorbing and biomedical sensing.

scholarly journals The multi-photon induced Fano effect

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
K. L. Litvinenko ◽  
Nguyen H. Le ◽  
B. Redlich ◽  
C. R. Pidgeon ◽  
N. V. Abrosimov ◽  
...  
Keyword(s):  
Shape Index ◽  
Bound State ◽  
Destructive Interference ◽  
Autoionizing State ◽  
Fano Effect ◽  
Coupling Laser ◽  
Weak Beam ◽  
Laser Control ◽  
Fast Control ◽  
The Continuum

AbstractThe ordinary Fano effect occurs in many-electron atoms and requires an autoionizing state. With such a state, photo-ionization may proceed via pathways that interfere, and the characteristic asymmetric resonance structures appear in the continuum. Here we demonstrate that Fano structure may also be induced without need of auto-ionization, by dressing the continuum with an ordinary bound state in any atom by a coupling laser. Using multi-photon processes gives complete, ultra-fast control over the interference. We show that a line-shape index q near unity (maximum asymmetry) may be produced in hydrogenic silicon donors with a relatively weak beam. Since the Fano lineshape has both constructive and destructive interference, the laser control opens the possibility of state-selective detection with enhancement on one side of resonance and invisibility on the other. We discuss a variety of atomic and molecular spectroscopies, and in the case of silicon donors we provide a calculation for a qubit readout application.

scholarly journals Perfect absorption of flexural waves induced by bound state in the continuum

2021 ◽  
pp. 101364
Author(s):  
Liyun Cao ◽  
Yifan Zhu ◽  
Sheng Wan ◽  
Yi Zeng ◽  
Yong Li ◽  
...  
Keyword(s):  
Bound State ◽  
Flexural Waves ◽  
Perfect Absorption ◽  
The Continuum

scholarly journals Bound in the continuum modes in indirectly-patterned hyperbolic media

2021 ◽  
Author(s):  
Frank Koppens ◽  
Hanan Herzig-Sheinfux ◽  
Lorenzo Orsini ◽  
Minwoo Jung ◽  
Iacopo Torre ◽  
...  
Keyword(s):  
Near Field ◽  
Optical Cavity ◽  
Bound State ◽  
Destructive Interference ◽  
Dramatic Improvement ◽  
Quality Factors ◽  
Strong Light ◽  
Sensing Applications ◽  
The Continuum ◽  
Nanoscale Level

Abstract A conventional optical cavity supports one or more modes, which are confined since they are unable to leak out of the cavity. Bound state in continuum (BIC) cavities are an unconventional alternative, based on confinement by destructive interference, even though optical leakage channels are available. BICs are a general wave phenomenon, of particular interest to optics, but BICs have never been demonstrated at the nanoscale level. Nanoscale BIC cavities are more challenging to realize, however, as they require destructive interference at the nanometer scale. Here, we demonstrate the first nanophotonic cavities based on BIC and find an unprecedented combination of quality factors and ultrasmall mode volume. In particular, we exploit hyperbolic media, HyM, as they can support large (in principle unlimited) momentum excitations, which propagate as ultra-confined rays, so that HyM cavities can in principle be extremely small. However, building a hyperbolic BIC (hBIC) cavity presents a fundamental challenge: an hBIC has an infinite number of modes, which would all need to interfere simultaneously. Here, we bring the BIC concept to the nanoscale by introducing and demonstrating a novel multimodal reflection mechanism of the ray-like optical excitations in hyperbolic materials. Using near-field microscopy, we demonstrate mid-IR confinement in BIC-based nanocavities with volumes down to 23x23x3〖nm〗^3 and quality factors above 100 – a dramatic improvement in several metrics of confinement. This alliance of HyM with BICs yields a radically novel way to confine light and is expected to have far reaching consequences wherever strong optical confinement is utilized, from ultra-strong light-matter interactions, to mid-IR nonlinear optics and a range of sensing applications.

scholarly journals Monolayer-graphene-based broadband and wide-angle perfect absorption structures in the near infrared

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Yansong Fan ◽  
Chucai Guo ◽  
Zhihong Zhu ◽  
Wei Xu ◽  
Fan Wu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Monolayer Graphene ◽  
Wide Angle ◽  
Perfect Absorption

Visible to near-infrared coherent perfect absorption in monolayer graphene

2018 ◽  
Vol 20 (9) ◽  
pp. 095401 ◽  
Author(s):  
Feng Xiong ◽  
Jinglan Zhou ◽  
Wei Xu ◽  
Zhihong Zhu ◽  
Xiaodong Yuan ◽  
...  
Keyword(s):  
Near Infrared ◽  
Monolayer Graphene ◽  
Perfect Absorption ◽  
Coherent Perfect Absorption

scholarly journals Monolayer-graphene-based perfect absorption structures in the near infrared

2017 ◽  
Vol 25 (12) ◽  
pp. 13079 ◽  
Author(s):  
Y. S. Fan ◽  
C. C. Guo ◽  
Z. H. Zhu ◽  
W. Xu ◽  
F. Wu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Monolayer Graphene ◽  
Perfect Absorption

scholarly journals A Tunable Triple-Band Near-Infrared Metamaterial Absorber Based on Au Nano-Cuboids Array

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 207 ◽  
Author(s):  
Feng Qin ◽  
Zeqiang Chen ◽  
Xifang Chen ◽  
Zao Yi ◽  
Weitang Yao ◽  
...  
Keyword(s):  
Surface Plasmons ◽  
Near Infrared ◽  
Structural Parameters ◽  
Fdtd Method ◽  
Field Enhancement ◽  
Metamaterial Absorber ◽  
Infrared Band ◽  
Perfect Absorption ◽  
Tunable Metamaterial ◽  
Triple Band

In this article, we present a design for a triple-band tunable metamaterial absorber with an Au nano-cuboids array, and undertake numerical research about its optical properties and local electromagnetic field enhancement. The proposed structure is investigated by the finite-difference time domain (FDTD) method, and we find that it has triple-band tunable perfect absorption peaks in the near infrared band (1000–2500 nm). We investigate some of structure parameters that influence the fields of surface plasmons (SP) resonances of the nano array structure. By adjusting the relevant structural parameters, we can accomplish the regulation of the surface plasmons resonance (SPR) peaks. In addition, the triple-band resonant wavelength of the absorber has good operational angle-polarization-tolerance. We believe that the excellent properties of our designed absorber have promising applications in plasma-enhanced photovoltaic, optical absorption switching and infrared modulator optical communication.

Sign in / Sign up

Export Citation Format

Share Document