scholarly journals Red-Shift Effects in Surface Enhanced Raman Spectroscopy: Spectral or Intensity Dependence of the Near-Field?

2016 ◽  
Vol 120 (25) ◽  
pp. 13675-13683 ◽  
Author(s):  
Florent J. Colas ◽  
Maximilien Cottat ◽  
Raymond Gillibert ◽  
Nicolas Guillot ◽  
Nadia Djaker ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Near Field ◽  
Surface Enhanced Raman Spectroscopy ◽  
Red Shift ◽  
Intensity Dependence ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

scholarly journals Freeform 3D Plasmonic Superstructures

2020 ◽  
Author(s):  
Won-Geun Kim ◽  
Jongmin Lee ◽  
Vasanthan Devaraj ◽  
Minjun Kim ◽  
Hyuk Jeong ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Near Field ◽  
Surface Enhanced Raman Spectroscopy ◽  
Far Field ◽  
Plasmonic Nanoparticle ◽  
Surface Enhanced ◽  
Nanoparticle Clusters ◽  
Surface Enhanced Raman

Abstract Plasmonic nanoparticle clusters promise to support various, unique artificial electromagnetisms at optical frequencies, realizing new concept devices for diverse nanophotonic applications. However, the technological challenges associated with the fabrication of plasmonic clusters with programmed geometry and composition remain unresolved. Here, we present a freeform fabrication of hierarchical plasmonic clusters (HPCs) based on omnidirectional guiding of evaporative self-assembly of gold nanoparticles (AuNPs) with the aid of 3D printing. Our method offers a facile, universal route to shape the multiscale features of HPCs in three-dimensions, leading to versatile manipulation of both far-field and near-field characteristics. Various functional nanomaterials can be effectively coupled to plasmonic modes of the HPCs by simply mixing with AuNP ink. We demonstrate in particular an ultracompact surface-enhanced Raman spectroscopy (SERS) platform to detect M13 viruses and their mutations from femtolitre volume, sub-100pM analytes. This SERS microplatform could pave the way towards simple, innovative detection methods of diverse pathogens, which is in high demand for handling pandemic situations. We expect our method to freely design and realize nanophotonic structures beyond the restrictions of traditional fabrication processes. Plasmonic nanoparticle clusters have attracted great attention due to the unique capability to manipulate electromagnetic fields at the sub-wavelength scale1–5. Ensembles of metallic nanoparticles generate various electromagnetisms at optical frequencies such as artificial magnetism6–10 and Fano-like interference11–13 and a strong field localization in the structure14–16. These unique properties are geometry-dependent and lead to a broad range of applications in sensing16,17, surface-enhanced spectroscopies18–22, nonlinear integrated photonics23,24, and light harvesting25,26. Traditionally, plasmonic clusters with tailored size and geometry are fabricated on substrates by top-down processes such as electron-beam lithography4,5 or focused-ion beam milling27,28. These approaches suffer from low throughput and are generally limited to in-plane fabrication. Alternatively, the self-assembly of colloids has been proposed as a versatile, high-throughput, and cost-effective route. A number of clever methods based on chemical linking (e.g., DNA origami)29–30 and/or convective assembly on lithographically structured templates25,26,31 have been devised to construct 2D or 3D plasmonic clusters. The shape formation, however, is mostly constrained by the thermodynamic impetus and/or template geometry. A significant challenge would be overcome these restrictions and expand structural design freedom in the fabrication of plasmonic cluster architectures with symmetry-breaking geometries. In this work, we develop a freeform, programmable 3D assembly of of hierarchical plasmonic clusters (HPCs). By exploiting micronozzle 3D printing, we demonstrate highly localized, omnidirectional meniscus-guided assembly of metallic nanoparticles, constructing a freestanding HPC with a tailored geometry that can control the far-field character. Our approach also allows versatile manipulation and exploitation of the near-field interaction in the HPC by a facile heterogeneous nanoparticle mixing. We demonstrate that 3D-printed HPCs can be utilized as an ultracompact surface-enhanced Raman spectroscopy (SERS) platform to detect M13 viruses and their mutations from femtolitre volume, sub-100pM analytes.

HAMR Emulation Using Plasmonic SERS Sensor As Near Field Transducer

2018 ◽  
Author(s):  
M. Yanagisawa ◽  
M. Kunimoto ◽  
M. Saito ◽  
T. Homma
Keyword(s):  
Raman Spectroscopy ◽  
Laser Heating ◽  
Heating Temperature ◽  
Near Field ◽  
Surface Enhanced Raman Spectroscopy ◽  
Lubricant Film ◽  
Wide Range ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Continuous Power

A plasmonic Surface-enhanced Raman Spectroscopy (SERS) sensor has been used for emulation of Near Field Transducer (NFT) in Heat-Assisted Magnetic Recording (HAMR). Laser heating mechanism by the sensor is the same as that by NFT with electro-magnetic near-field or plasmonic field, which is different from far field heating. Heating behavior for a lubricant film on a carbon overcoat for a hard disk medium was observed using Surface-enhanced Raman Spectroscopy with the plasmonic SERS sensor. Spectral change of lube films in laser heating with a continuous power changer was measured with heating temperature, calculated by anti-Stokes/Stokes intensity ratio in Raman spectra. As a result, it is found that the lubricant film composed of a tetraol perfluoro-polyether (PFPE) is evaporated above 290°C, which shows good agreement with that by TGA (Thermogravimetric Analysis). The evaporation occurs in wide range of spacing between the lubricant film and the SERS sensor from 0 (contact) to 50nm, and more. After laser heating, lubricant film with free surface in a large gap area, i.e. spacing of 3nm, is recovered with elapsed time. However it is difficult to be recovered in confined (contact) area, because lubricant mobility is small. Lost lubricant can be recovered in head flying by surface diffusion or centrifugal force during disk rotation.

scholarly journals Surface-Enhanced Raman Spectroscopy of Dye and Thiol Molecules Adsorbed on Triangular Silver Nanostructures: A Study of Near-Field Enhancement, Localization of Hot-Spots, and Passivation of Adsorbed Carbonaceous Species

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Manuel R. Gonçalves ◽  
Fabian Enderle ◽  
Othmar Marti
Keyword(s):  
Raman Spectroscopy ◽  
Hot Spots ◽  
Near Field ◽  
Field Enhancement ◽  
Surface Enhanced Raman Spectroscopy ◽  
Spherical Particles ◽  
Silver Nanostructures ◽  
Dye Molecules ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Surface-enhanced Raman spectroscopy (SERS) of thiols and dye molecules adsorbed on triangular silver nanostructures was investigated. The SERS hot-spots are localized at the edges and corners of the silver triangular particles. AFM and SEM measurements permit to observe many small clusters formed at the edges of triangular particles fabricated by nanosphere lithography. Finite-element calculations show that near-field enhancements can reach values of more than 200 at visible wavelengths, in the gaps between small spherical particles and large triangular particles, although for the later no plasmon resonance was found at the wavelengths investigated. The regions near the particles showing strong near-field enhancement are well correlated with spatial localization of SERS hot-spots done by confocal microscopy. Silver nanostructures fabricated by thermal evaporation present strong and fast fluctuating SERS activity, due to amorphous carbon contamination. Thiols and dye molecules seem to be able to passivate the undesired SERS activity on fresh evaporated silver.

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