Angle dependent surface enhanced Raman scattering obtained from a Ag nanorod array substrate

Liu, Yongjun; Fan, Jiayan; Zhao, Yiping; Shanmukh, Saratchandra; Dluhy, Richard A.

doi:10.1063/1.2369644

Cited by 86 publications

(83 citation statements)

References 23 publications

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“…In contrast, the non-linearity in the thiophenol signal is quite different to silicon and therefore indicates anisotropic scattering from the SERS substrate. This observation is in keeping with previous results from a variety of SERS substrates [10,11]. Table 1 and was calculated according to the relationship given in the Appendix).…”

Section: Samples and Methodssupporting

confidence: 65%

“…4(c), the islands are 60 nm high and are placed on top of a solid 30-nm Ag layer. This second structure is somewhat analogous to the Ag nanorod on the Ag film substrate fabricated by Liu et al [11], also using oblique angle deposition. In both layouts, the structure is illuminated by an x-polarized linear plane-wave source, tilted by an angle φ with respect to the z-axis, to highlight the contribution of waves at the beam boundary angle in each of the cases listed in Table 1.…”

Section: Numerical Simulationmentioning

confidence: 99%

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Light enhancement in surface-enhanced Raman scattering at oblique incidence

et al. 2012

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Surface enhanced Raman scattering (SERS) measurements have been carried out at different focusing conditions using objective lenses of different numerical apertures. The experimentally observed dependence of SERS intensity of thiophenol-coated Ag nano-islands shows a close-to-linear scaling with the collection aperture. The linear relationship breaks down for large numerical apertures, which suggests that the scattering is anisotropic. Numerical simulations of realistically shaped Ag nano-islands were carried out, and the spatial distribution of hot-spots has been revealed at different heights near the nano-islands. Local field enhancements of up to 100 times were estimated. The simulation also suggests an explanation for the anisotropy in the scattering observed for larger numerical aperture objectives. This appears to be due to a reduction in the local field enhancement as the electric field vector component in the plane of the shallow metal islands reduces at larger angles of incidence.

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Section: Samples and Methodssupporting

confidence: 65%

Section: Numerical Simulationmentioning

confidence: 99%

Light enhancement in surface-enhanced Raman scattering at oblique incidence

et al. 2012

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“…28,29 Semicontinuous gold films support both localized and delocalized surface plasmon modes and have a much stronger local field enhancement than continuous thin film. 30 Both the metallic nanorod array and semicontinuous film are commonly used as SERS substrates due to large local field enhancements, [31][32][33][34][35][36][37][38][39] so the plasmon coupling in our nanorod-film hybrid is also expected to further enhance the local field and improve the sensitivity of SERS. In our studies, the long-axis SPR of the Au nanorod array is tuned by adjusting the rod length and the SPR of the semicontinuous Au film is tuned by controlling the sputtering deposition time.…”

mentioning

confidence: 99%

“…30 Both the metallic nanorod array and semicontinuous film are commonly used as SERS substrates due to large local field enhancements, [31][32][33][34][35][36][37][38][39] …”

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confidence: 99%

Tuning Gold Nanorod-Nanoparticle Hybrids into Plasmonic Fano Resonance for Dramatically Enhanced Light Emission and Transmission

et al. 2010

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We investigate the optical response of a gold nanorod array coupled with a semicontinuous nanoparticle film. We find that, as the gold nanoparticle film is adjusted to the percolating regime, the nanorod-film hybrids are tuned into plasmonic Fano resonance, characterized by the coherent coupling of discrete plasmonic modes of the nanorod array with the continuum band of the percolating film. Consequently, optical transmission of the percolating film is substantially enhanced. Even more strikingly, electromagnetic fields around the nanorod array become much stronger, as reflected by 2 orders of magnitude enhancement in the avalanche multiphoton luminescence. These findings may prove instrumental in the design of various plasmonic nanodevices.KEYWORDS Plasmonic Fano resonance, plasmon hybrid, gold percolating film, gold nanorod array, enhanced transmission, enhanced photoluminescence E xtensive research efforts have been devoted recently to utilizing metal nanostructures to manipulate the propagation, intensity, and polarization of light, [1][2][3][4][5][6] leading to the emergence of nanophotonics as a major new direction in photonics. In this emerging field, one central physical entity is plasmon, characterizing the collective excitation of conduction electrons in metal nanostructures. Many intriguing phenomena discovered recently, such as the squeezing of light into subwavelength nanoholes, 7-9 and the detection of molecules trapped between nanogaps via surface-enhanced Raman scattering (SERS) with single molecule sensitivity, [10][11][12] are tied to the coupling of incident light with plasmon modes. Such studies not only broaden our fundamental understanding of photon interaction with nanoscale systems, but also may have far-reaching technological impacts.In exploration of various intriguing plasmonic phenomena at the nanoscale, a widely studied and distinctive research emphasis is the exploitation of the coupling and hybridization of different plasmon modes supported by various elegantly fabricated metal nanostructures. [13][14][15][16][17][18][19][20][21][22] Compelling examples include the plasmon coupling of a discrete mode to a continuum band, known as the "plasmonic Fano resonance". The Fano type absorption spectra were first reported in hole arrays in thin metal films and coaxial metallic arrays due to interferences of localized and delocalized plasmon modes.23-25 A more vivid picture of the plasmonic Fano model with three interaction regimes was convincingly demonstrated in metallic nanoparticle-film systems by tuning the film thickness. 26 Recently, multiple Fano resonances in a metallic ring/disk dimer and twinned Fano resonances in the Au-Ag heteronanorod dimer were also reported. 27 Most research focused on the asymmetric Fano line-shape in the absorption spectra, but enhanced emissions and Raman scattering induced by constructive interferences via the plasmonic Fano effect are seldom explored, which is of great importance for both passive and active plasmonic nanosystems.In this Letter, ...

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“…24 It is shown that the EM enhancement strongly depends on the particle size, shape, the separation of the particles, dielectric environment and arrangement. [25][26][27] Consequently, various methods have been taken to improve the EM enhancement of Ag NR array, including adjusting the length of Ag NR, varying the deposition angle, 28 changing the incident angle of the excitation laser 29 and altering the shape of NR. Recently, researchers have prepared plenty of structures like the square helical NR, 30 the L-shaped NR 31 and the folding straight Ag NRs into zig-zag structures.…”

Section: Introductionmentioning

confidence: 99%

Performance Improving Method of Aligned Silver Nanorod by Grafting Au@Ag Core–Shell Nanoparticles for Surface-Enhanced Raman Scattering

Chen

Dong

Wang

et al. 2017

NANO

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A simple method for improving surface-enhanced Raman scattering (SERS) performance of aligned silver nanorod (Ag NR) array was investigated. This method was to construct a kind of hybrid substrate by grafting Au@Ag core-shell nanoparticles (NPs) into Ag NR array using poly (2-vinylphridine) (P2VPy) as a bridging agent. The hybrid substrate yielded excellent SERS performance as its detection limit improved from 10 À6 M to 10 À8 M using trans-1,2-bis(4-pyridyl) ethylene (BPE) as probe molecule, which was increased by two orders of magnitude compared with Ag NR array substrate. The signi¯cant improvement of SERS performance of Ag NR arrays was attributed to the addition of Au@Ag core-shell NPs. As a result of surface plasmon resonance generated by the interaction of electromagnetic (EM) (IAEM)¯led between NP and NR structures, increasing hotspots were found at the connections of NPs and NRs, the gaps of adjacent rods, and the gaps of two particles consequently. These results were validated by the¯nite di®erence time domain (FDTD) calculation. Besides, hybrid substrate shows good performance in stability and reproducibility. The proposed method was simple and robust, which promoted SERS performance of Ag NR array e®ectively, showing great potential in the application of SERS substrate fabrication and SERS-based bio-chemical sensing.

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Angle dependent surface enhanced Raman scattering obtained from a Ag nanorod array substrate

Cited by 86 publications

References 23 publications

Light enhancement in surface-enhanced Raman scattering at oblique incidence

Light enhancement in surface-enhanced Raman scattering at oblique incidence

Tuning Gold Nanorod-Nanoparticle Hybrids into Plasmonic Fano Resonance for Dramatically Enhanced Light Emission and Transmission

Performance Improving Method of Aligned Silver Nanorod by Grafting Au@Ag Core–Shell Nanoparticles for Surface-Enhanced Raman Scattering

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