scholarly journals Dimerized high contrast gratings

Nanophotonics ◽  
2018 ◽  
Vol 7 (6) ◽  
pp. 1157-1168 ◽  
Author(s):  
Adam C. Overvig ◽  
Sajan Shrestha ◽  
Nanfang Yu
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Period Doubling ◽  
Building Blocks ◽  
Optical Modulator ◽  
Refractive Index Sensor ◽  
Spectral Features ◽  
High Contrast ◽  
Index Contrast ◽  
Lateral Localization

AbstractMetasurfaces and planar photonic crystals are two classes of subwavelength diffractive optical devices offering novel functionalities. The former employ independently operating subwavelength “meta-units” as their building blocks, while the latter exploit the collective response of many periodic building blocks. High contrast gratings (HCGs) are an example of one-dimensional (1D) planar photonic crystals with large refractive index contrast, exhibiting large in-plane scattering even with a limited number of grating periods. They are best known for their broadband features. Low contrast gratings (LCGs) are known for their control over sharp spectral features but require many periods due to small in-plane scattering. We explore a class of symmetry-broken HCGs called dimerized high contrast gratings (DHCGs), which have a period-doubling perturbation applied. DHCGs support modes accessible by free-space illumination with a long, controllable photon lifetime (inversely proportional to the magnitude of the perturbation) and reduced lateral energy divergence (confined by the high index contrast of the grating). We catalogue and clarify the resonant modes introduced by the dimerizing perturbation in 1D DHCGs and briefly explore the increased in-plane scattering present in two-dimensional (2D) DHCGs. We introduce an approach maximizing lateral localization by band structure engineering in the unperturbed HCG and using the dimerizing perturbation to generate sharp spectral features in devices with small footprint. We confirm the simultaneous control of photon lifetime and lateral localization with full-wave simulations of finite-sized DHCGs. We conclude by numerically demonstrating two compact devices (an optical modulator and a refractive index sensor) benefitting from the unique design freedoms of DHCGs.

Coupling Properties of Defect Modes in Organic Octagonal Quasiperiodic-Photonic-Crystals Under Low-Refractive-Index Contrast

2018 ◽  
Vol 38 (2) ◽  
pp. 0216003
Author(s):  
蔡园园 Cai Yuanyuan ◽  
王智 Wang Zhi ◽  
陈笑 Chen Xiao ◽  
李长伟 Li Changwei ◽  
冯帅 Feng Shuai ◽  
...  
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Defect Modes ◽  
Refractive Index Contrast ◽  
Index Contrast ◽  
Low Refractive Index

Single-Frequency Refractive Index Sensor Based on a Finite One-Dimensional Photonic Crystals with Two Defects

2006 ◽  
Vol 45 (8B) ◽  
pp. 6754-6758 ◽  
Author(s):  
H. Alatas ◽  
H. Mayditia ◽  
H. Hardhienata ◽  
A. A. Iskandar ◽  
M. O. Tjia
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Single Frequency ◽  
Refractive Index Sensor ◽  
One Dimensional

scholarly journals Analysis of Scattering by Plasmonic Gratings of Circular Nanorods Using Lattice Sums Technique

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3923
Author(s):  
Jandieri ◽  
Yasumoto ◽  
Pistora ◽  
Erni
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Electromagnetic Scattering ◽  
Near Field ◽  
Planar Geometry ◽  
Refractive Index Sensor ◽  
Infinite Length ◽  
Absorption Bands ◽  
Lattice Sums ◽  
Plasmonic Gratings

A self-contained formulation for analyzing electromagnetic scattering by a significant class of planar gratings composed of plasmonic nanorods, which were infinite length along their axes, is presented. The procedure for the lattice sums technique was implemented in a cylindrical harmonic expansion method based on the generalized reflection matrix approach for full-wave scattering analysis of plasmonic gratings. The method provided a high computational efficiency and can be considered as one of the best-suited numerical tools for the optimization of plasmonic sensors and plasmonic guiding devices both having a planar geometry. Although the proposed formalism can be applied to analyze a wide class of plasmonic gratings, three configurations were studied in the manuscript. Firstly, a multilayered grating of silver nanocylinders formed analogously to photonic crystals was considered. In the region far from the resonances of a single plasmonic nanocylinder, the structure showed similar properties compared to conventional photonic crystals. When one or a few nanorods were periodically removed from the original crystal, thus forming a crystal with defects, a new band was formed in the spectral responses because of the resonant tunneling through the defect layers. The rigorous formulation of plasmonic gratings with defects was proposed for the first time. Finally, a plasmonic planar grating of metal-coated dielectric nanorods coupled to the dielectric slab was investigated from the viewpoint of design of a refractive index sensor. Dual-absorption bands attributable to the excitation of the localized surface plasmons were studied, and the near field distributions were given in both absorption bands associated with the resonances on the upper and inner surfaces of a single metal-coated nanocylinder. Resonance in the second absorption band was sensitive to the refractive index of the background medium and could be useful for the design of refractive index sensors. Also analyzed was a phase-matching condition between the evanescent space-harmonics of the plasmonic grating and the guided modes inside the slab, leading to a strong coupling.

An ultrahigh-contrast and broadband on-chip refractive index sensor based on a surface-plasmon-polariton interferometer

The Analyst ◽  
2015 ◽  
Vol 140 (21) ◽  
pp. 7263-7270 ◽  
Author(s):  
Yujia Wang ◽  
Jianjun Chen ◽  
Chengwei Sun ◽  
Kexiu Rong ◽  
Hongyun Li ◽  
...  
Keyword(s):  
Refractive Index ◽  
Surface Plasmon ◽  
Surface Plasmon Polariton ◽  
Refractive Index Sensor ◽  
High Contrast ◽  
Plasmonic Sensors ◽  
High Figure ◽  
Plasmon Polariton ◽  
On Chip

By using a novel optical illumination scheme, high-contrast and broadband plasmonic sensors with ultra-high figure of merits are experimentally demonstrated.

scholarly journals GaN-Based High-Contrast Grating for Refractive Index Sensor Operating Blue–Violet Wavelength Region

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4444
Author(s):  
Yuusuke Takashima ◽  
Masanobu Haraguchi ◽  
Yoshiki Naoi
Keyword(s):  
Refractive Index ◽  
Chemical Stability ◽  
Simple System ◽  
Refractive Index Sensor ◽  
Field Calculation ◽  
High Contrast ◽  
High Chemical ◽  
Wide Range ◽  
High Contrast Grating ◽  
High Chemical Stability

Owing to its versatility, optical refractive index (RI) sensors with compact size and high chemical stability are very suitable for a wide range of the applications in the internet of things (IoT), such as immunosensor, disease detection, and blood mapping. In this study, a RI sensor with very simple system and high chemical stability was developed using GaN-based high-contrast grating (HCG). The designed HCG pattern was fabricated on GaN-film grown on c-plane sapphire substrate. The fabricated GaN-HCG sensor can detect minuscule RI change of 1.71 × 10–3 with extreme simple surface normal irradiation system. The light behavior inside the GaN-HCG was discussed using numerical electromagnetic field calculation, and the deep understand of the sensing mechanism was provided. The simple system and very high chemical stability of our sensor exploit RI sensing applications in IoT society.

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