Plasmonic Sensing Characteristics of Gold Nanorods with Large Aspect Ratios

Plasmonic gold nanorods play important roles in nowadays state-of-the-art plasmonic sensing techniques. Most of the previous studies and applications focused on gold nanorods with relatively small aspect ratios, where the plasmon wavelengths are smaller than 900 nm. Gold nanorods with large aspect ratios are predicted to exhibit high refractive-index sensitivity (Langmir 2008, 24, 5233–5237.), which therefore should be promising for developing of high-performance plasmonic chemical- and bio-sensors. In this study, we developed gold nanorods with aspect ratios over 7.9, which exhibit plasmon resonances around 1064 nm. The refractive index (RI) sensitivity of these nanorods have been evaluated by varying their dielectric environment, whereby a sensitivity as high as 473 nm/RIU can be obtained. Furthermore, we have demonstrated the large-aspect-ratio nanorods as efficient substrate for surface enhanced Raman spectroscopy (SERS), where an enhancement factor (EF) as high as 9.47×108 was measured using 4-methylbenzenethiol (4-MBT) as probe molecule. Finally, a type of flexible SERS substrate is developed by conjugating the gold nanorods with the polystyrene (PS) polymer. The results obtained in our study can benefit the development of plasmonic sensing techniques utilized in the near-infrared spectral region.

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Plasmonic Sensing Characteristics of Gold Nanorods with Large Aspect Ratios

Sensors ◽

10.3390/s18103458 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3458 ◽

Cited By ~ 6

Author(s):

Chao Zhuang ◽

Yifan Xu ◽

Ningsheng Xu ◽

Jinxiu Wen ◽

Huanjun Chen ◽

...

Keyword(s):

Refractive Index ◽

Gold Nanorods ◽

High Performance ◽

Near Infrared ◽

High Refractive Index ◽

Surface Enhanced Raman Spectroscopy ◽

Sers Substrate ◽

Refractive Index Sensitivity ◽

Aspect Ratios ◽

Plasmonic Sensing

Plasmonic gold nanorods play important roles in nowadays state-of-the-art plasmonic sensing techniques. Most of the previous studies and applications focused on gold nanorods with relatively small aspect ratios, where the plasmon wavelengths are smaller than 900 nm. Gold nanorods with large aspect ratios are predicted to exhibit high refractive-index sensitivity (Langmir 2008, 24, 5233–5237), which therefore should be promising for the development of high-performance plasmonic chemical- and bio-sensors. In this study, we developed gold nanorods with aspect ratios over 7.9, which exhibit plasmon resonances around 1064 nm. The refractive index (RI) sensitivity of these nanorods have been evaluated by varying their dielectric environment, whereby a sensitivity as high as 473 nm/RIU (refractive index unit) can be obtained. Furthermore, we have demonstrated the large-aspect-ratio nanorods as efficient substrate for surface enhanced Raman spectroscopy (SERS), where an enhancement factor (EF) as high as 9.47 × 108 was measured using 4-methylbenzenethiol (4-MBT) as probe molecule. Finally, a type of flexible SERS substrate is developed by conjugating the gold nanorods with the polystyrene (PS) polymer. The results obtained in our study can benefit the development of plasmonic sensing techniques utilized in the near-infrared spectral region.

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Active Electromagnetically Induced Transparency Effect in Graphene-Dielectric Hybrid Metamaterial and Its High-Performance Sensor Application

Nanomaterials ◽

10.3390/nano11082032 ◽

2021 ◽

Vol 11 (8) ◽

pp. 2032

Author(s):

Fan Gao ◽

Peicheng Yuan ◽

Shaojun Gao ◽

Juan Deng ◽

Zhiyu Sun ◽

...

Keyword(s):

Refractive Index ◽

Near Infrared ◽

Slow Light ◽

Electromagnetically Induced Transparency ◽

High Refractive Index ◽

Infrared Region ◽

Refractive Index Sensitivity ◽

Index Sensitivity ◽

Induced Transparency ◽

Hybrid Metamaterial

Electromagnetically induced transparency (EIT) based on dielectric metamaterials has attracted attentions in recent years because of its functional manipulation of electromagnetic waves and high refractive index sensitivity, such as high transmission, sharp phase change, and large group delay, etc. In this paper, an active controlled EIT effect based on a graphene-dielectric hybrid metamaterial is proposed in the near infrared region. By changing the Fermi level of the top-covered graphene, a dynamic EIT effect with a high quality factor (Q-factor) is realized, which exhibits a tunable, slow, light performance with a maximum group index of 2500. Another intriguing characteristic of the EIT effect is its high refractive index sensitivity. In the graphene-covered metamaterial, the refractive index sensitivity is simulated as high as 411 nm/RIU and the figure-of-merit (FOM) is up to 159, which outperforms the metastructure without graphene. Therefore, the proposed graphene-covered dielectric metamaterial presents an active EIT effect in the near infrared region, which highlights its great application potential in deep optical switching, tunable slow light devices, and sensitive refractive index sensors, etc.

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High-sensitivity refractive index of Au@Cu2−xS core–shell nanorods

RSC Advances ◽

10.1039/c8ra07711h ◽

2018 ◽

Vol 8 (61) ◽

pp. 35005-35013 ◽

Cited By ~ 1

Author(s):

Pengfei Cao ◽

Huizhen Chen ◽

Hailong Zhang ◽

Lin Cheng ◽

Tiaoming Niu

Keyword(s):

Refractive Index ◽

Near Infrared ◽

High Sensitivity ◽

High Refractive Index ◽

Core Shell ◽

Refractive Index Sensitivity ◽

Index Sensitivity

A high refractive index sensitivity of Au@Cu2−xS core–shell nanorods working in the near-infrared is theoretically demonstrated.

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Raman scattering in high-refractive-index nanostructures

Nanophotonics ◽

10.1515/nanoph-2020-0539 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Søren Raza ◽

Anders Kristensen

Keyword(s):

Raman Spectroscopy ◽

Refractive Index ◽

Raman Scattering ◽

Bound States ◽

Stimulated Raman Scattering ◽

Dielectric Materials ◽

High Refractive Index ◽

Surface Enhanced Raman Spectroscopy ◽

Raman Enhancement ◽

The Impact

AbstractThe advent of resonant dielectric nanomaterials has provided a new path for concentrating and manipulating light on the nanoscale. Such high-refractive-index materials support a diverse set of low-loss optical resonances, including Mie resonances, anapole states, and bound states in the continuum. Through these resonances, high-refractive-index materials can be used to engineer the optical near field, both inside and outside the nanostructures, which opens up new opportunities for Raman spectroscopy. In this review, we discuss the impact of high-refractive-index nano-optics on Raman spectroscopy. In particular, we consider the intrinsic Raman enhancement produced by different dielectric resonances and their theoretical description. Using the optical reciprocity theorem, we derive an expression which links the Raman enhancement to the enhancement of the stored electric energy. We also address recent results on surface-enhanced Raman spectroscopy based on high-refractive-index dielectric materials along with applications in stimulated Raman scattering and nanothermometry. Finally, we discuss the potential of Raman spectroscopy as a tool for detecting the optical near-fields produced by dielectric resonances, complementing reflection and transmission measurements.

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Mode Sensitivity Exploration of Silica–Titania Waveguide for Refractive Index Sensing Applications

Sensors ◽

10.3390/s21227452 ◽

2021 ◽

Vol 21 (22) ◽

pp. 7452

Author(s):

Muhammad A. Butt ◽

Andrzej Kaźmierczak ◽

Cuma Tyszkiewicz ◽

Paweł Karasiński ◽

Ryszard Piramidowicz

Keyword(s):

Refractive Index ◽

High Performance ◽

Near Infrared ◽

Sol Gel ◽

Cost Effective ◽

Dip Coating ◽

Infrared Wavelength ◽

Refractive Index Sensing ◽

Sensing Applications ◽

Coating Method

In this paper, a novel and cost-effective photonic platform based on silica–titania material is discussed. The silica–titania thin films were grown utilizing the sol–gel dip-coating method and characterized with the help of the prism-insertion technique. Afterwards, the mode sensitivity analysis of the silica–titania ridge waveguide is investigated via the finite element method. Silica–titania waveguide systems are highly attractive due to their ease of development, low fabrication cost, low propagation losses and operation in both visible and near-infrared wavelength ranges. Finally, a ring resonator (RR) sensor device was modelled for refractive index sensing applications, offering a sensitivity of 230 nm/RIU, a figure of merit (FOM) of 418.2 RIU−1, and Q-factor of 2247.5 at the improved geometric parameters. We believe that the abovementioned integrated photonics platform is highly suitable for high-performance and economically reasonable optical sensing devices.

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A robust high refractive index sensitivity fiber Mach–Zehnder interferometer fabricated by femtosecond laser machining and chemical etching

Sensors and Actuators A Physical ◽

10.1016/j.sna.2015.04.006 ◽

2015 ◽

Vol 230 ◽

pp. 111-116 ◽

Cited By ~ 29

Author(s):

Xiaoyan Sun ◽

Xinran Dong ◽

Youwang Hu ◽

Haitao Li ◽

Dongkai Chu ◽

...

Keyword(s):

Refractive Index ◽

Femtosecond Laser ◽

Chemical Etching ◽

High Refractive Index ◽

Zehnder Interferometer ◽

Laser Machining ◽

Refractive Index Sensitivity ◽

Index Sensitivity ◽

Mach Zehnder Interferometer

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Nano-thick-dielectric encapsulation effects on the refractive index sensitivities of Ag plane-nanosphere-cluster sensors

Modern Physics Letters B ◽

10.1142/s021798491850080x ◽

2018 ◽

Vol 32 (08) ◽

pp. 1850080 ◽

Cited By ~ 1

Author(s):

Chao Ling Du ◽

Wan Chun Yang ◽

Sheng Peng ◽

Da Ning Shi

Keyword(s):

Refractive Index ◽

Localized Surface Plasmon ◽

Great Promise ◽

Sers Substrate ◽

Refractive Index Sensitivity ◽

Surface Enhanced Raman ◽

Equilateral Triangles ◽

Quadratic Response ◽

The Stability ◽

Index Sensitivity

The nano-thick-dielectric encapsulation effects on the bulk and local refractive index sensitivity behaviors of Ag plane-nanosphere-cluster sensors (including nanosphere monomers, dimers, trimer chains and trimer equilateral triangles, four kinds of normally encountered nanoparticles in experiments) have been numerically investigated by finite element method (FEM). The encapsulation is revealed to decrease the quadratic magnitude of the refractive index responses of their peak wavelengths of localized surface plasmon resonances (LSPR), while it does not violate such quadratic response natures. Its effect on their capabilities of surface enhanced Raman scattering (SERS) behaviors is discussed too. It is demonstrated to provide an efficient type of SERS substrate for plasmonic sensing and detections, which improves the stability of the concerned nanoparticles, and not diminish their SERS signals, in agreement well with experiments under the same nanostructure parameters. This work holds great promise for further designing SERS-based sensing/detecting substrates and sensors/detectors.

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Anodic Alumina Photonic Crystals as Refractive Index Sensors for Controlling the Composition of Liquid Mixtures

Photonic Sensors ◽

10.1007/s13320-019-0569-2 ◽

2019 ◽

Vol 10 (2) ◽

pp. 147-154 ◽

Cited By ~ 6

Author(s):

Matin Ashurov ◽

Vladimir Gorelik ◽

Kirill Napolskii ◽

Sergey Klimonsky

Keyword(s):

Refractive Index ◽

Photonic Crystals ◽

Stop Band ◽

Analytical Signal ◽

Liquid Mixtures ◽

High Refractive Index ◽

Anodic Alumina ◽

Refractive Index Sensitivity ◽

Water Glycerol ◽

Refractive Index Sensors

Abstract Photonic crystals based on anodic aluminum oxide films are examined as refractive index sensors for controlling the composition of water-alcohol liquid mixtures. The position of the reflectance maximum corresponding to the first photonic stop band is used as the analytical signal. Impregnation of a photonic crystal with water-ethanol and water-glycerol mixtures results in a redshift of the reflectance maximum. A fairly high refractive index sensitivity, sufficient to determine the composition of water-ethanol and water-glycerol mixtures with an accuracy of about 1 wt.%, is observed. The detailed dependencies of the analytical signal on the composition of mixtures are experimentally investigated and compared with numerical calculations. Prospects and limitations of the refractive index sensors based on anodic alumina photonic crystals are discussed.

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