Gold Nanoparticles at a Liquid Interface: Towards a Soft Nonlinear Metasurface

Optical second-harmonic generation (SHG) is achieved using adsorbed gold nanoparticles (AuNPs) with an average diameter of 16 nm at the aqueous solution–air interface in reflection. A detailed analysis of the depth profile of the SHG intensity detected shows that two contributions appear in the over...

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Bibliographic Details
Main Authors: Delphine Schaming, Anthony Maurice, Frédéric Gumy, Micheál D. Scanlon, Christian Jonin, Hubert H. Girault, Pierre-François Brevet
Format: Article
Language:English
Published: MDPI AG 2024-08-01
Series:Photonics
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Online Access:https://www.mdpi.com/2304-6732/11/9/789
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Summary:Optical second-harmonic generation (SHG) is achieved using adsorbed gold nanoparticles (AuNPs) with an average diameter of 16 nm at the aqueous solution–air interface in reflection. A detailed analysis of the depth profile of the SHG intensity detected shows that two contributions appear in the overall signal, one arising from the aqueous solution–air interface that is sensitive to the AuNP surface excess and one arising from the bulk aqueous phase. The latter is an incoherent signal also known as hyper-Rayleigh scattering (HRS). The results agree with those of an analysis involving Gaussian beam propagation optics and a Langmuir-like isotherm. Discrepancies are revealed for the largest AuNP concentrations used and indicate a new route for the design of soft metasurfaces.
ISSN:2304-6732