Local field enhancements on gold and silver nanostructures for aperture near field spectroscopy

Laverdant, Julien; Quélin, Xavier

doi:10.1016/j.jlumin.2007.02.050

Cited by 11 publications

(6 citation statements)

References 19 publications

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“…SNOM analysis has been carried out in order to clarify the spatial localization of the hot spots (sites of strong field scattering) on the sample surface. The ability of aperture SNOM in measuring the field intensity is limited in the case of densely nanostructured surfaces as, for instance, semicontinuous gold films produced at the limit of percolation , or randomly distributed nanostructures . This is a consequence of the impossibility for the apertured near-field probe to approach very close to the surface in the case of randomly distributed nanostructures consisting of nanosized holes or pores.…”

Section: Resultsmentioning

confidence: 99%

SERS Enhancement and Field Confinement in Nanosensors Based on Self-Organized Gold Nanowires Produced by Ion-Beam Sputtering

et al. 2014

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ince its discovery, surface-enhanced Raman spectroscopy (SERS) has pushed researchers' interest to develop different kinds of active substrates for high sensitivity molecular detection. Defocused ion beam sputtering (IBS) represents a viable route for the production of large scale, highly reproducible SERS-active substrates consisting of near-field coupled nanowires featuring localized surface plasmon resonances in the visible and the near-infrared. Here we investigate the field enhancement and spatial confinement in the visible and the near-infrared of arrays of optically resonant gold nanowires, using two complementary techniques: SERS and scanning near-field optical microscopy (SNOM). While SERS allows us to quantify the field enhancement factor, SNOM is used to image the localization of the enhanced electromagnetic fields. We show that in the visible (633 nm) the nanowires are SERS active only for excitation polarized parallel to the wire-to-wire nanocavities, yielding enhancement factors of 7 × 103. In the near-infrared (785 nm) we observe a 2-fold larger SERS enhancement (1.3 × 104) for excitation parallel to the nanocavities and detect the onset of SERS amplification for excitation polarization parallel to the nanowires long axis. Polarization-sensitive SNOM in the near-infrared (830 nm) enables the correlation of the scattered intensity with the sample morphology at the local scale. We demonstrate that the field enhancement stems from the wire-to-wire nanocavity regions when the excitation field is polarized parallel to the wire-to-wire nanocavity, while we observe more complex field confinement patterns related to the partially inhomogeneous morphology of the substrate when the polarization is parallel to the nanowires long axis. Our experiments strongly suggest IBS-fabricated nanowires as novel substrates for plasmon-enhanced spectroscopie

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Section: Resultsmentioning

confidence: 99%

SERS Enhancement and Field Confinement in Nanosensors Based on Self-Organized Gold Nanowires Produced by Ion-Beam Sputtering

et al. 2014

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“…39 The typical control of probe– sample interaction is based on shear forces measured with a tuning fork or with a standard AFM controller. 40 If the optical excitation (or the detection) is passing through the aperture, the excitation (or detection) is qualified as “near field” while the detection (or the excitation) is performed in the “far field.” Different configurations of near- and far-field excitation and detection can be performed. For the study of plasmonic nanostructures, a variety of optical signals can be measured using SNOM (fluorescence, luminescence, elastically or inelastically light scattered, second or third harmonic generation, etc.).…”

Section: Optical Near-field Microscopymentioning

confidence: 99%

Imaging the Optical near Field in Plasmonic Nanostructures

Merlen

Lagugné‐Labarthet

2014

Appl Spectrosc

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Over the past five years, new developments in the field of plasmonics have emerged with the goal of finely tuning a variety of metallic nanostructures to enable a desired function. The use of plasmonics in spectroscopy is of course of great interest, due to large local enhancements in the optical near field confined in the vicinity of a metal nanostructure. For a given metal, such enhancements are dependent on the shape of the structure as well as the optical properties (wavelength, phase, polarization) of the impinging light, offering a large degree of control over the optical and spatial localization of the plasmon resonance. In this focal point, we highlight recent work that aims at revealing the spatial position of the localized plasmon resonances using a variety of optical and non-optical methods.

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“…In addition, Quelin and coworkers have developed a statistical method for characterizing the strength of NSOM-monitored field enhancements on discontinuous Au films to suggest ideal substrate architectures for SERS. 120 Near-field scanning optical microscopy resolution has traditionally been limited to ϳ50 to 100 nm based on the skin-depth of aluminum used for fabrication of nanoscale aperture probes. To overcome this limitation, apertureless NSOM (ANSOM) has been implemented using metallic or dielectric tip-scattered light as an evanescent field source near the sam-ple.…”

Section: Fig 7 First Direct Evidence Of Surface Plasmon Polariton-lmentioning

confidence: 99%

Recent Advances in Nanomaterial Plasmonics: Fundamental Studies and Applications

2008

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Local field enhancements on gold and silver nanostructures for aperture near field spectroscopy

Cited by 11 publications

References 19 publications

SERS Enhancement and Field Confinement in Nanosensors Based on Self-Organized Gold Nanowires Produced by Ion-Beam Sputtering

SERS Enhancement and Field Confinement in Nanosensors Based on Self-Organized Gold Nanowires Produced by Ion-Beam Sputtering

Imaging the Optical near Field in Plasmonic Nanostructures

Recent Advances in Nanomaterial Plasmonics: Fundamental Studies and Applications

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