On the physical contributions to the third-order nonlinear optical response in plasmonic nanocomposites

Roberto Carlos Fernández-Hernández, Roberto Gleason-Villagran, Carlos Torres-Torres, Luis Rodríguez-Fernández, Alejandro Crespo-Sosa, Juan Carlos Cheang-Wong, Alejandra López-Suárez, Raúl Rangel-Rojo, Alicia Oliver, Jorge Alejandro Reyes-Esqueda

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Abstract

Au and Ag isotropic and anisotropic nanocomposites were prepared using the ion implantation technique. Their optical properties were studied at several wavelengths in the optical range 300-800 nm, across their plasmon resonances. The linear regime was characterized by measuring the absorption spectrum and the third-order nonlinear regime by means of the Z-scan technique using a tunable picosecond pulsed laser system (26 ps). Open-aperture Z-scan traces show a superposition of different optical nonlinear absorption (NLA) processes in the whole range studied. We associate these phenomena with the excitation of inter- and intra-band electronic transitions, which contribute with a positive sign to NLA, and to the formation of hot-electrons, which contribute with opposite sign to NLA. Closed-aperture traces for measuring nonlinear refraction (NLR) show different signs for Au and Ag samples, and a change of sign in Au is found when purely inter-band transitions are excited. In this work, for the appropriate wavelength, it is worth remarking on the free-electron response to the exciting light and its strong contribution to the nonlinear optical properties for low (intra-band) and high (hot-electrons) irradiances. © 2012 IOP Publishing Ltd.
Original languageAmerican English
JournalJournal of Optics (United Kingdom)
DOIs
StatePublished - 1 Dec 2012

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Fernández-Hernández, R. C., Gleason-Villagran, R., Torres-Torres, C., Rodríguez-Fernández, L., Crespo-Sosa, A., Cheang-Wong, J. C., López-Suárez, A., Rangel-Rojo, R., Oliver, A., & Reyes-Esqueda, J. A. (2012). On the physical contributions to the third-order nonlinear optical response in plasmonic nanocomposites. Journal of Optics (United Kingdom). https://doi.org/10.1088/2040-8978/14/12/125203