scholarly journals Refractive index sensing by asymmetric dielectric gratings with both bound states in the continuum and guided mode resonances

2021 ◽  
Author(s):  
Chuanbao Liu ◽  
Yang Bai ◽  
Ji Zhou ◽  
Junhong Chen ◽  
Lijie Qiao
Keyword(s):  
Refractive Index ◽  
Bound States ◽  
Refractive Index Sensing ◽  
Guided Mode ◽  
Dielectric Gratings ◽  
The Continuum

scholarly journals Refractive index sensing with optical bound states in the continuum

2020 ◽  
Vol 28 (26) ◽  
pp. 38907
Author(s):  
Dmitrii N. Maksimov ◽  
Valeriy S. Gerasimov ◽  
Silvia Romano ◽  
Sergey P. Polyutov
Keyword(s):  
Refractive Index ◽  
Bound States ◽  
Refractive Index Sensing ◽  
The Continuum

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 Optical Waveguides with Compound Multiperiodic Grating Nanostructures for Refractive Index Sensing

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Lars Thorben Neustock ◽  
Sabrina Jahns ◽  
Jost Adam ◽  
Martina Gerken
Keyword(s):  
Refractive Index ◽  
Optical Waveguides ◽  
Spectral Characteristics ◽  
Quality Factors ◽  
Refractive Index Sensitivity ◽  
Refractive Index Sensing ◽  
Guided Mode ◽  
Duty Cycles ◽  
Rigorous Coupled Wave ◽  
Index Sensitivity

The spectral characteristics and refractive index sensitivity of compound multiperiodic grating waveguides are investigated in theory and experiment. Compound gratings are formed by superposition of two or more monoperiodic gratings. Compared to monoperiodic photonic crystal waveguides, compound grating waveguides offer more degrees of design freedom by choice of component grating periods and duty cycles. Refractive index sensing is achieved by evaluating the wavelength or intensity of guided mode resonances in the reflection spectrum. We designed, fabricated, and characterized 24 different compound multiperiodic nanostructured waveguides for refractive index sensing. Simulations are carried out with the Rigorous Coupled Wave Algorithm (RCWA). The resulting spectra, resonance sensitivities, and quality factors are compared to monoperiodic as well as to three selected aperiodic nanostructures (Rudin-Shapiro, Fibonacci, and Thue-Morse). The refractive index sensitivity of the TE resonances is similar for all types of investigated nanostructures. For the TM resonances the compound multiperiodic nanostructures exhibit higher sensitivity values compared to the monoperiodic nanostructure and similar values as the aperiodic nanostructures. No significant influence of the compound grating duty cycles on the sensitivity is observed.

Ultrasensitive Surface Refractive Index Imaging Based on Quasi-Bound States in the Continuum

ACS Nano ◽  
2020 ◽  
Vol 14 (11) ◽  
pp. 15417-15427 ◽  
Author(s):  
Silvia Romano ◽  
Maria Mangini ◽  
Erika Penzo ◽  
Stefano Cabrini ◽  
Anna Chiara De Luca ◽  
...  
Keyword(s):  
Refractive Index ◽  
Bound States ◽  
The Continuum

scholarly journals Extended bound states in the continuum in a one-dimensional grating implemented on a distributed Bragg reflector

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Emilia Pruszyńska-Karbownik ◽  
Mikołaj Janczak ◽  
Tomasz Czyszanowski
Keyword(s):  
Refractive Index ◽  
Bound States ◽  
High Refractive Index ◽  
Bragg Reflector ◽  
Distributed Bragg Reflector ◽  
Optical Cavities ◽  
One Dimensional ◽  
Optical Modes ◽  
High Degree ◽  
The Continuum

Abstract Bound states in the continuum (BICs) are observed in optical cavities composed of a high refractive index periodic structure embedded in significantly lower refractive index surroundings, enabling vertical confinement of the grating modes. Here, we propose a vertically nonsymmetric configuration, implemented on a high refractive index bulk substrate with a one-dimensional grating positioned on a distributed Bragg reflector (DBR). In this configuration, the grating modes are leaky, which could prohibit the creation of a BIC if the grating was implemented on uniform substrate. However, the judiciously designed DBR on which the grating is implemented reflects nonzero diffraction orders induced by the grating. We found that the laterally antisymmetric optical modes located at the center of the Brillouin zone of this structure create BICs that are robust against changes in the grating parameters, as long as the DBR reflects the diffraction orders. The configuration enables a high degree of design freedom, facilitating the realization of very high quality factor cavities in conventional all-semiconductor technology.

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