Probing the out-of-plane optical response of plasmonic nanostructures using spectroscopic ellipsometry

Highly ordered self-assembled silver nanoparticle (NP) arrays have been produced by glancing angle deposition on faceted c-plane Al 2 O 3 templates. The NP shape can be tuned by changing the substrate temperature during deposition. Reflectance anisotropy spectroscopy has been used to monitor the plasmonic evolution of the sample during the growth. The structures showed a strong dichroic response related to NP anisotropy and dipolar coupling. Furthermore, multipolar resonances due to sharp edge effects between NP and substrate were observed. Analytical and numerical methods have been used to explain the results and extract semi-quantitative information on the morphology of the NPs. The results provide insight on the growth mechanisms by the glancing angle deposition. Finally, it has been shown that the NP morphology can be manipulated by a simple illumination the surface with an intense light source, inducing changes in the optical response. This opens up new possibilities for engineering plasmonic structure over large active areas.

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“…The effective dielectric function of such a NP layer along the i-th direction is given by [47][48][49] …”

Section: Theory and Discussionmentioning

confidence: 99%

Manipulating and probing the growth of plasmonic nanoparticle arrays using light

et al. 2013

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“…The Ag/Al 2 O 3 system was produced by glancing angle deposition of Ag, using a technique described by Verre et al [16,17], on vicinal α-Al 2 O 3 under high vacuum conditions (base pressure of 2×10 −8 mbar). The sapphire substrate is annealed for 24 hours at 1400 • C, producing an ordered and faceted structure.…”

Section: Methodsmentioning

confidence: 99%

“…Specifically, all pressure ranges of gas-solid interfaces are accessible, the material damage and contamination associated with charged particle probes is eliminated, and insulating substrates can be studied without the problem of charging effects [15]. For example, it has been shown recently that reflection anisotropy spectroscopy (RAS), a surface sensitive form of polarized reflectance, is a particularly useful in situ probe of Ag NP growth on faceted Al 2 O 3 [7,16], while spectroscopic ellipsometry combined with analytic modelling of the optical response also appears promising [17,18].…”

Section: Introductionmentioning

confidence: 99%

Optical characterisation of plasmonic nanostructures on planar substrates using second–harmonic generation

et al. 2015

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Abstract:Off-normal, polarization dependent second-harmonic generation (SHG) measurements were performed ex situ on plasmonic nanostructures grown by self-assembly on nanopatterned templates. These exploratory studies of Ag nanoparticle (NP) arrays show that the sensitivity of SHG to the local fields, which are modified by the NP size, shape and distribution, makes it a promising fixed wavelength characterization technique that avoids the complexity of spectroscopic SHG. The off-normal geometry provides access to the out-of-plane SH response, which is typically an order-of-magnitude larger than the in-surface-plane response measured using normal incidence, for example in SHG microscopy. By choosing the plane of incidence orthogonal to the NP array direction, it was shown that the p−polarized SH response, as a function of input polarization, is very sensitive to NP morphology, with a change of 20% in the aspect ratio of the NPs producing a variation of a factor of 30 in the easily measureable ratio of the p−polarized SH field strength for s− and p−polarized input. The results show that such a fixed geometry could be used for the in situ characterization of anisotropic nanostructure morphology during growth by self-assembly, which could be particularly useful in situations where rotating the sample may be neither desirable nor easily accomplished. Rep. 408, 131-314 (2005). 34. G. Bachelier and J. Butet and I. Russier-Antoine and C. Jonin and E.Benichou and P. F. Brevet, "Origin of optical second-harmonic generation in spherical gold nanoparticles: local surface and nonlocal bulk contributions," Phys.

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“…18 For this reason, the number of studies of plasmonic structures using SE is still limited. [22][23][24][25][26][27] Previously it was demonstrated by our group 28 that a quantity, named anisotropic surface excess function (ASEF), could be extracted from the experiment and the response of ultrathin plasmonic layer (<10 nm) directly analyzed. The advantage of ASEF is that it depends only on the optical properties of the plasmonic layer, allowing the modeling of the nanocomposite layer alone.…”

Section: Introductionmentioning

confidence: 99%

General approach to the analysis of plasmonic structures using spectroscopic ellipsometry

et al. 2013

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In this article a route to analyze the full optical response of plasmonic structures is developed. First, the simple case of an anisotropic thin plasmonic layer supported on a transparent substrate is analyzed by introducing a quantity named anisotropic surface excess function (ASEF). The spectral features are analyzed in terms of effective dielectric function, demonstrating a more direct relation with the plasmonic response of the layer. The formalism is then generalized using a transfer matrix method. The formalism developed is supported by experimental evidence obtained by measuring the response of anisotropic nanoparticle arrays grown at a glancing angle. The agreement between theory and experiment is clear, suggesting that SE can be conveniently employed to measure the spectroscopic response of plasmonic structures. It is also demonstrated that the figure of merit of the plasmonic resonance for refractive index sensing can be greatly improved, with optimized measurement configurations, using polarized spectroscopy.

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Probing the out-of-plane optical response of plasmonic nanostructures using spectroscopic ellipsometry

Cited by 27 publications

References 39 publications

Manipulating and probing the growth of plasmonic nanoparticle arrays using light

Manipulating and probing the growth of plasmonic nanoparticle arrays using light

Optical characterisation of plasmonic nanostructures on planar substrates using second–harmonic generation

General approach to the analysis of plasmonic structures using spectroscopic ellipsometry

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