Optical Properties of Au, Ag, and Bimetallic Au on Ag Nanohole Arrays

Murray-Méthot, Marie-Pier; Ratel, Mathieu; Masson, Jean-François

doi:10.1021/jp101231c

Cited by 74 publications

(80 citation statements)

References 55 publications

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“…When the two holes overlap, two sharp apexes are created and act as an optical antenna that focuses the electromagnetic field to very small region at the sharp apexes [178]. Murray-Méthot and coworkers [179] recently investigated the optical properties and analytical response such as sensitivity, transmission intensity, and FWHM of various arrays. Ag and Au arrays with different periodicities, diameters and bimetallic nanoholes were examined.…”

Section: Laser and Photonics Reviewsmentioning

confidence: 99%

Sensitivity‐enhancement methods for surface plasmon sensors

Shalabney

Abdulhalim

2011

Laser & Photonics Reviews

443

254

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Surface plasmon resonance (SPR) sensors have been a mature technology for more than two decades now, however, recent investigations show continuous enhancement of their sensitivity and their lower detection limit. Together with the recent investigations in localized SPR phenomena, extraordinary optical transmission through nanoapertures in metals, and surface-enhanced spectroscopies, drastic developments are expected to revolutionize the field of optical biosensing. Sensitivity-enhancement (SE) techniques are reviewed focusing both on the physical transduction mechanisms and the system performance. In the majority of cases the SE is associated with the enhancement of the electromagnetic field overlap integral describing the interaction energy within the analyte. Other important mechanisms are the interaction between plasmons and excitons and between the analyte molecules and the metal surface. The lower detection limit can be reduced significantly if systems with high signal-to-noise ratio are used such as common-path interferometry, ellipsometry or polarimetry systems.

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Section: Laser and Photonics Reviewsmentioning

confidence: 99%

Sensitivity‐enhancement methods for surface plasmon sensors

Shalabney

Abdulhalim

2011

Laser & Photonics Reviews

443

254

View full text Add to dashboard Cite

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“…Recently, it was also demonstrated that the intensity of enhanced transmission in nanohole arrays was improved for bimetallic films, using a Ag underlayer and a Au overlayer. 14 Other examples include FON substrates composed of Au multilayers with silver oxide island films. 35 The authors demonstrated that the films are more stable to oxidation and they have an improved Raman response.…”

Section: Effect Of the Metal Film Composition On Raman Amplificationmentioning

confidence: 99%

Surface-Enhanced Raman Spectroscopy Amplification with Film over Etched Nanospheres

2010

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Polymer nanosphere lithography (NSL) masks were etched in oxygen plasma prior to metal deposition, which tunes the localized surface plasmon resonance (LSPR) and the interparticle distance resulting in greater Raman amplification than conventional film over nanosphere (FON). Various nanosphere masks were investigated, using nanosphere sizes of 220, 360, 450, 520, and 650 nm etched from 0 (conventional FON) to 10 min. Thereby, the film over etched nanospheres (FOEN) amplifies by up to a factor of 4 the Raman response of 4-nitrobenzenethiol (4-NBT) on Ag as compared to unetched FON. The LSPR response of FOEN and SEM analysis of the gap distance revealed that the optimal amplification results from a combination of tuning the gap (a gap/diameter of less than 1 improves the Raman response), matching the laser excitation wavelength (633 and 785 nm both investigated), and an increasing roughness of FOEN. Metal multilayers of Ag and Au were also deposited to investigate the effect on the Raman and LSPR response. While the LSPR response remains relatively invariable, the Raman signal from 4-NBT decreased significantly by increasing the number of layers when Ag is used as the outer layer. However, a bimetallic film composed of Ag underlayer with Au as an outerlayer further increased the Raman response by a factor of 1.6. Overall, the most intense Raman response for FOEN was obtained with 360 nm nanospheres, etched for 1.5 min to create a gap of 66 nm with an overall bimetallic film thickness of 175 nm, which was composed of an Ag underlayer of 87.5 nm and an Au outerlayer of 87.5 nm. Thus, by performing these simple modifications to FON, the Raman response can be increased by nearly 1 order of magnitude.

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“…7 Nanohole arrays offer great promise for various applications, including theoretical investigation of light-surface plasmon interactions, 1 biosensing, 8,9 plasmon-enhanced photovoltaics, 10 spectro-electrochemistry, 11 and surface enhanced spectroscopy. 12,13 The optical properties of nanohole arrays are well understood for different hole diameters, 14 periodicities, 15 and metal compositions. 14 However, grating coupling conditions remain poorly characterized and uncertainty remains concerning the importance of symmetry (S, rotation symmetry of 60 for hexagonal arrays), incidence angle (q) and azimuthal rotation (f) for sensing and optical ltering.…”

Section: Introductionmentioning

confidence: 99%

Tuning the 3D plasmon field of nanohole arrays

et al. 2013

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Modern photonics is being revolutionized through the use of nanostructured plasmonic materials, which confine light to sub-diffraction limit resolution providing universal, sensitive, and simple transducers for molecular sensors. Understanding the mechanisms by which light interacts with plasmonic crystals is essential for developing application-focussed devices. The strong influence of grating coupling on electromagnetic field distribution, frequency and degeneracy of plasmon bands has now been characterized using hexagonal nanohole arrays. An equation for nanohole arrays was derived to demonstrate the strong influence of incidence and rotation angle on optical properties of 2D plasmonic crystals such as nanohole arrays. Consequently, we report experimental data that are in strong agreement with finite difference time-domain (FDTD) simulations that clearly demonstrate the influence of the grating coupling conditions on the optical properties (such as plasmon degeneracy and bandwidth), and on the distribution of the plasmon field around nanohole arrays (including tuneable penetration depths and highly localized fields). The tuneable 3D plasmon field allowed for controlled sensing properties and by increasing the angle of incidence to 30 degrees, the resonance wavelength was tuned from 1000 to 600 nm, and the sensitivity was enhanced by nearly 300% for a protein assay using surface plasmon resonance (SPR) and by 40% with surface-enhanced Raman scattering (SERS) sensors.

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Optical Properties of Au, Ag, and Bimetallic Au on Ag Nanohole Arrays

Cited by 74 publications

References 55 publications

Sensitivity‐enhancement methods for surface plasmon sensors

Sensitivity‐enhancement methods for surface plasmon sensors

Surface-Enhanced Raman Spectroscopy Amplification with Film over Etched Nanospheres

Tuning the 3D plasmon field of nanohole arrays

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