Imaging of surface plasmon polariton fields excited at a nanometer-scale slit

Zhang, Lingxiao; Kubo, Atsushi; Wang, Leiming; Petek, Hrvoje; Seideman, Tamar

doi:10.1103/physrevb.84.245442

Cited by 92 publications

(115 citation statements)

References 55 publications

(81 reference statements)

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“…The polaritons can be detected by a variety of techniques, among them holographic recording [11], observation of SPP-induced stray light with a camera [7], two-photon photo-emission electron microscopy [8,12], and SNOM [9,10]. Recently, the s-SNOM technique [1,13,14] was also employed, in this case to investigate SPPs on a gold film with a nano-trench etched into it.…”

Section: Introductionmentioning

confidence: 99%

“…SPPs on conductive surfaces have usually been excited by illumination of edges, trenches, and other surface disruptions with electromagnetic radiation, which has a component of the electrical radiation field perpendicular to the respective boundary [7][8][9][10]. The polaritons can be detected by a variety of techniques, among them holographic recording [11], observation of SPP-induced stray light with a camera [7], two-photon photo-emission electron microscopy [8,12], and SNOM [9,10].…”

Section: Introductionmentioning

confidence: 99%

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Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

et al. 2017

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Abstract:We investigated the excitation of surface plasmon polaritons on gold films with the metallized probe tip of a scattering-type scanning near-field optical microscope (s-SNOM). The emission of the polaritons from the tip, illuminated by near-infrared laser radiation, was found to be anisotropic and not circularly symmetric as expected on the basis of literature data. We furthermore identified an additional excitation channel via light that was reflected off the tip and excited the plasmon polaritons at the edge of the metal film. Our results, while obtained for a non-rotationally-symmetric type of probe tip and thus specific for this situation, indicate that when an s-SNOM is employed for the investigation of plasmonic structures, the unintentional excitation of surface waves and anisotropic surface wave propagation must be considered in order to correctly interpret the signatures of plasmon polariton generation and propagation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

et al. 2017

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“…While there is a good agreement of ω p and ∞ with many past measurements, our value of τ = 17 ± 3 fs is significantly shorter than the commonly used literature value from Johnson and Christy of 31 ± 12 fs [26] and the value derived from DC conductivity of ∼ 40 fs [27,28], yet consistent with most optical and plasmonic experiments, such as typical surface plasmon propagation length and particle plasmon resonance lifetimes. [21,23,25,29,30] The difference in τ between the DC and the optical frequency measurements is due to the frequency dependence of the scattering rate 1/τ (ω). [31,32] An analysis with extended Drude model extracts this frequency dependence, which is found to be consistent with Fermi liquid theory beyond 0.1 eV.…”

Section: Introductionmentioning

confidence: 99%

Optical dielectric function of silver

et al. 2015

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The dielectric function of silver is a fundamental quantity related to its electronic structure and describes its optical properties. However, results published over the past six decades are in part inconsistent and exhibit significant discrepancies. The measurement is experimentally challenging with the values of dielectric function spanning over five orders of magnitude from the mid-infrared to the visible/ultraviolet spectral range. Using broadband spectroscopic ellipsometry, we determine the complex valued dielectric function of evaporated and template stripped polycrystalline silver films from 0.05 eV (λ = 25 µm) to 4.14 eV (λ = 300 nm) with a statistical uncertainty of less than 1%. From Drude analysis of the 0.1 -3 eV range, values of the plasma frequency ω p = 8.9 ± 0.2 eV, dielectric function at infinite frequency ∞ = 5 ± 2, and relaxation time τ = 1/Γ = 17 ± 3 fs are obtained, with the absolute uncertainties estimated from systematic errors and experimental repeatability. Further analysis based on the extended Drude model reveals an increase in τ with decreasing frequency in agreement with Fermi liquid theory, and extrapolates to τ 22 fs for zero frequency. A deviation from simple Fermi liquid behavior is suggested at energies below 0.1 eV (λ = 12 µm) with the onset of a further increase in τ connecting to the DC value from transport measurements of ∼ 40 fs. The results are consistent with a wide range of optical and plasmonic experiments throughout the infrared and visible/ultraviolet spectral range. The influence of grain boundaries, defect scattering, and surface oxidation is discussed. The results are compared with our previous measurements of the dielectric function of gold [Phys. Rev. B 86, 235147 (2012)].

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“…The probability of multiphoton excitation is typically low; however, LSPRassisted local field enhancement can promote the multiphoton excitation of metallic nanostructures and render MP-PEEM suitable for direct imaging of the near-field LSPR. The combination of MP-PEEM with pump-probe techniques, namely, time-resolved MP-PEEM (TR-MP-PEEM), 32,38,39 was established to investigate the dynamics of LSPR and the propagating surface plasmon polariton. Two-photon PEEM investigations have typically been performed on Ag nanostructures excited by near-ultraviolet femtosecond laser pulses (,400 nm, double frequency of a Ti:sapphire laser).…”

Section: Introductionmentioning

confidence: 99%

Direct imaging of the near field and dynamics of surface plasmon resonance on gold nanostructures using photoemission electron microscopy

et al. 2013

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Localized surface plasmon resonance (LSPR) can be supported by metallic nanoparticles and engineered nanostructures. An understanding of the spatially resolved near-field properties and dynamics of LSPR is important, but remains experimentally challenging. We report experimental studies toward this aim using photoemission electron microscopy (PEEM) with high spatial resolution of sub-10 nm. Various engineered gold nanostructure arrays (such as rods, nanodisk-like particles and dimers) are investigated via PEEM using near-infrared (NIR) femtosecond laser pulses as the excitation source. When the LSPR wavelengths overlap the spectrum of the femtosecond pulses, the LSPR is efficiently excited and promotes multiphoton photoemission, which is correlated with the local intensity of the metallic nanoparticles in the near field. Thus, the local field distribution of the LSPR on different Au nanostructures can be directly explored and discussed using the PEEM images. In addition, the dynamics of the LSPR is studied by combining interferometric time-resolved pump-probe technique and PEEM. Detailed information on the oscillation and dephasing of the LSPR field can be obtained. The results identify PEEM as a powerful tool for accessing the near-field mapping and dynamic properties of plasmonic nanostructures. Keywords: femtosecond laser; local field enhancement; near-field imaging; photoemission electron microscopy; surface plasmon resonance INTRODUCTION Because of the rapid development of nanofabrication techniques, metallic nanostructures that can exhibit localized surface plasmon resonance (LSPR) can be fabricated using several methods. The resonance frequency and amplitude of LSPR on metallic nanostructures are known to depend on the metal materials, shapes, and surrounding media. [1][2][3][4] In addition, the LSPR can confine optical fields in nanoscale space, leading to the so-called local field enhancement effect. These unique properties promote the application of LSPR in many fields, such as surface-enhanced Raman scattering, 5-8 sensing, 1,9,10 plasmonassisted photochemical reactions 4,11,12 and photocurrent generation. [13][14][15] To further understand the LSPR mechanism and to optimize the design of the plasmonic nanostructures for most applications, the near-field properties of the LSPR fields (especially the near-field distribution of the plasmonic nanostructures) must be determined. To date, investigations of the optical properties of LSPR have largely relied on far-field spectroscopic techniques or numerical simulations. Several experimental approaches have been utilized to visualize the near field, including scanning photoionization microscopy, 16,17 scanning near-field optical microscopy, 18-21 nonlinear luminescence or fluorescent microscopy, 22,23 nonlinear photopolymerization 24,25 and near-field ablation of a substrate. [26][27][28][29] However, these approaches have

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Imaging of surface plasmon polariton fields excited at a nanometer-scale slit

Cited by 92 publications

References 55 publications

Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

Optical dielectric function of silver

Direct imaging of the near field and dynamics of surface plasmon resonance on gold nanostructures using photoemission electron microscopy

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