Large-volume hot spots in gold spiky nanoparticle dimers for high-performance surface-enhanced spectroscopy

Nanoscale ◽  
2014 ◽  
Vol 6 (21) ◽  
pp. 12921-12928 ◽  
Author(s):  
Anran Li ◽  
Shuzhou Li
Keyword(s):  
Electric Field ◽  
Large Volume ◽  
Hot Spots ◽  
High Performance ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Large Electric Field ◽  
Surface Enhanced ◽  
Performance Surface

Hot spots with both large electric field enhancement and large volumes can be obtained in spiky nanoparticle dimers.

Gold nanonails for surface-enhanced infrared absorption

2020 ◽  
Vol 5 (8) ◽  
pp. 1200-1212
Author(s):  
Hang Yin ◽  
Nannan Li ◽  
Yubing Si ◽  
Han Zhang ◽  
Baocheng Yang ◽  
...  
Keyword(s):  
Electric Field ◽  
Infrared Absorption ◽  
Colloidal Gold ◽  
Field Enhancement ◽  
Infrared Region ◽  
Electric Field Enhancement ◽  
Mid Infrared ◽  
Large Electric Field ◽  
Surface Enhanced

Colloidal gold nanonails, exhibiting large electric field enhancement in the mid-infrared region, are synthesized for surface-enhanced infrared absorption (SEIRA).

scholarly journals Study on surface enhanced Raman scattering of Au and Au@Al2O3 spherical dimers based on 3D finite element method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bao-xin Yan ◽  
Yan-ying Zhu ◽  
Yong Wei ◽  
Huan Pei
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Field ◽  
Raman Scattering ◽  
Enhancement Factor ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

AbstractIn this paper, the surface enhanced Raman scattering (SERS) characteristics of Au and Au@Al2O3 nanoparticle dimers were calculated and analyzed by using finite element method (3D-FEM). Firstly, the electric field enhancement factors of Au nanoparticles at the dimer gap were optimized from three aspects: the incident angle of the incident light, the radius of nanoparticle and the distance of the dimer. Then, aluminum oxide is wrapped on the Au dimer. What is different from the previous simulation is that Al2O3 shell and Au core are regarded as a whole and the total radius of Au@Al2O3 dimer is controlled to remain unchanged. By comparing the distance of Au nucleus between Au and Au@Al2O3 dimer, it is found that the electric field enhancement factor of Au@Al2O3 dimer is much greater than that of Au dimer with the increase of Al2O3 thickness. The peak of electric field of Au@Al2O3 dimer moves towards the middle of the resonance peak of the two materials, and it is more concentrated than that of the Au dimer. The maximum electric field enhancement factor 583 is reached at the shell thickness of 1 nm. Our results provide a theoretical reference for the design of SERS substrate and the extension of the research scope.

scholarly journals Dielectric-loading approach for extra electric field enhancement and spatially transferring plasmonic hot-spots

2020 ◽  
Vol 32 (3) ◽  
pp. 035205
Author(s):  
Mingjie Wan ◽  
Jingyu Wu ◽  
Jun Liu ◽  
Zhuo Chen ◽  
Ping Gu ◽  
...  
Keyword(s):  
Electric Field ◽  
Hot Spots ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Dielectric Loading

scholarly journals Study on Surface Enhanced Raman Scattering of Au and Au@Al2O3 Spherical Dimers Based on 3D Finite Element Method

2020 ◽  
Author(s):  
Baoxin Yan ◽  
Yanying Zhu ◽  
Yong Wei ◽  
Huan Pei
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Field ◽  
Enhancement Factor ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Peak Electric Field

Abstract In this paper, the surface enhanced Raman scattering (SERS) characteristics of Au and Au@Al2O3 nanoparticle dimers were calculated and analyzed by using finite element method (3D-FEM). Firstly, the electric field enhancement factors of Au nanoparticles at the dimer gap were optimized from three aspects: the incident angle of the incident light, the radius of nanoparticle and the distance of the dimer. Then, aluminum oxide is wrapped on the Au dimer. What is different from the previous simulation is that Al2O3 shell and Au core are regarded as a whole and the total radius of Au@Al2O3 dimer is controlled to remain unchanged. By comparing the distance of Au nucleus between Au and Au@Al2O3 dimer, it is found that the electric field enhancement factor of Au@Al2O3 dimer is much greater than that of Au dimer with the increase of Al2O3 thickness. The peak electric field of Au@Al2O3 dimer moves towards the middle of the resonance peak of the two materials, but the peak electric field of Au dimer is more concentrated than that of Au dimer, so that the excitation wavelength has less influence on Raman enhancement. The maximum electric field enhancement factor 583 is reached at the shell thickness of 1 nm. Our results provide a theoretical reference for the design of SERS substrate and the extension of the research scope.

scholarly journals Anapole-assisted giant electric field enhancement for surface-enhanced coherent anti-Stokes Raman spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryam Ghahremani ◽  
Mojtaba Karimi Habil ◽  
Carlos J. Zapata-Rodriguez
Keyword(s):  
Raman Spectroscopy ◽  
Electric Field ◽  
Hot Spots ◽  
Full Range ◽  
Design Procedure ◽  
Field Enhancement ◽  
Second Order ◽  
Valuable Insight ◽  
Surface Enhanced ◽  
Anti Stokes

AbstractThe coherent anti-Stokes Raman spectroscopy (CARS) techniques are recognized for their ability to detect and identify vibrational coherent processes down to the single-molecular levels. Plasmonic oligomers supporting full-range Fano-like line profiles in their scattering spectrum are one of the most promising class of substrates in the context of surface-enhanced (SE) CARS application. In this work, an engineered assembly of metallic disk-shaped nanoparticles providing two Fano-like resonance modes is presented as a highly-efficient design of SECARS substrate. We show that the scattering dips corresponding to the double-Fano spectral line shapes are originated from the mutual interaction of electric and toroidal dipole moments, leading to the so-called non-trivial first- and second-order anapole states. The anapole modes, especially the higher-order ones, can result in huge near-field enhancement due to their light-trapping capability into the so-called “hot spots”. In addition, independent spectral tunability of the second Fano line shape is exhibited by modulating the gap distance of the corner particles. This feature is closely related to the electric current loop associated with the corner particles in the second-order anapole state and provides a simple design procedure of an optimum SECARS substrate, where the electric field hot spots corresponding to three involved wavelengths, i.e., anti-Stokes, pump, and Stokes, are localized at the same spatial position. These findings yield valuable insight into the plasmonic substrate design for SECARS applications as well as for other nonlinear optical processes, such as four-wave mixing and multi-photon surface spectroscopy.

Realistic FDTD Simulations of Plasmonic Properties on Ag Columnar Thin Films as SERS Biosensor

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650113
Author(s):  
Yan-Juan Liao ◽  
Jing-Nan Huang ◽  
Jia-Yang Guo ◽  
Shao-Ji Jiang
Keyword(s):  
Thin Films ◽  
Electric Field ◽  
Hot Spots ◽  
Near Infrared ◽  
Structural Characteristics ◽  
Field Enhancement ◽  
Infrared Range ◽  
Electric Field Enhancement ◽  
Sem Images ◽  
Sculptured Thin Films

Noble metal sculptured thin films are of great interest during last decade as excellent surface-enhanced Raman scattering (SERS) substrates due to remarkable plasmonic properties in the visible and near-infrared range. In this work, Ag columnar thin films (Ag-CTFs) have been prepared by the glancing angle deposition technique. Finite-difference time-domain simulations has been utilized to study plasmonic properties of Ag-CTFs with a more accurate model based on binary scanning electron microscope (SEM) images by taking account of the shape irregularities, size distributions and random arrangement. The calculated absorption spectra based on the model of binarized SEM images show the best agreement with the measured spectra compared with models of periodic array with a regular shape. The near-field plasmonic properties are simulated based on the verified model. The distributions of electric field enhancement and hot spots are confirmed to be spectral and polarization dependent. There are multiple resonance peaks from visible to near-infrared and multiple eigenmodes coexist at the same wavelength and electric field enhancement are mainly excited by the polarized light vertical to the gap orientation. The electric field enhancement is found to distribute unevenly in the films with surface-localized feature. The equations to calculate the simulation SERS enhancement factor (EF) and total number of hot spots (tHN) are modified according to the above discussions. The experimental SERS EFs are on the order of 107–108, which indicates the high sensitivity of the films and the simulation SERS EFs and tHNs show good agreement with the experimental EFs. It is found that the SERS performance of Ag-CTFs is decided by both the cross-section structural characteristics and film thickness, which affect the electric filed enhancement and number of adsorbed molecules, respectively. Our work could be helpful in understanding the SERS mechanism and useful to the optimization of metal sculptured thin films for designing SERS biosensor.

Study of surface-enhanced Raman scattering of InAs particles of subwavelength apertures at terahertz frequencies

2015 ◽  
Vol 29 (31) ◽  
pp. 1550197 ◽  
Author(s):  
Ying Liu ◽  
Guangjun Ren ◽  
Rongjian Du ◽  
Yongming Zhang ◽  
Tianbo Tan ◽  
...  
Keyword(s):  
Electric Field ◽  
Enhancement Factor ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Subwavelength Apertures ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Theoretical Mechanism ◽  
Terahertz Frequencies

We present a theoretical mechanism for electric field enhancement with SERS of InAs particles of subwavelength apertures under THz excitation. The distribution of electric field confirms that there is a strong enhancement in the InAs particles at THz frequencies. The InAs with a Drude-like behavior in THz range, which is similar to metals at optical frequencies, leads to different SERS when the parameters of these two particles change. The SERS enhancement factor can reach [Formula: see text] under the certain conditions.

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