title: Resonant Enhancement of Second-Harmonic Generation in the Mid-Infrared Using Localized Surface Phonon Polaritons in Subdiffractional Nanostructures.
abstract: We report on the strong enhancement of mid-infrared second-harmonic generation (SHG) from SiC nanopillars due to the resonant excitation of localized surface phonon polaritons within the Reststrahlen band. A strong dependence of the SHG enhancement upon the optical mode distribution was observed. One such mode, the monopole, exhibits an enhancement that is beyond what is anticipated from field localization and dispersion of the linear and nonlinear SiC optical properties. Comparing the results for the identical nanostructures made of 4H and 6H SiC polytypes, we demonstrate the interplay of localized surface phonon polaritons with zone-folded weak phonon modes of the anisotropic crystal. Tuning the monopole mode in and out of the region where the zone-folded phonon is excited in 6H-SiC, we observe a further prominent increase of the already enhanced SHG output when the two modes are coupled. Envisioning this interplay as one of the showcase features of mid-infrared nonlinear nanophononics, we discuss its prospects for the effective engineering of nonlinear-optical materials with desired properties in the infrared spectral range.
authors: Physikalische Chemie, Fritz-Haber-Institut der MPG , Faradayweg 4-6, 14195 Berlin, Germany.
authors: Ilya
authors: I
authors: Razdolski
authors: The Blackett Laboratory, Imperial College London , London SW7 2AZ, United Kingdom.|Department of Electrical and Computer Engineering, National University of Singapore , 117583 Singapore.
authors: Yiguo
authors: Y
authors: Chen
authors: U.S. Naval Research Laboratory , 4555 Overlook Avenue SW, Washington, D.C. 20375, United States.
authors: Alexander J
authors: AJ
authors: Giles
authors: Physikalische Chemie, Fritz-Haber-Institut der MPG , Faradayweg 4-6, 14195 Berlin, Germany.
authors: Sandy
authors: S
authors: Gewinner
authors: Physikalische Chemie, Fritz-Haber-Institut der MPG , Faradayweg 4-6, 14195 Berlin, Germany.
authors: Wieland
authors: W
authors: Schöllkopf
authors: Department of Electrical and Computer Engineering, National University of Singapore , 117583 Singapore.
authors: Minghui
authors: M
authors: Hong
authors: Physikalische Chemie, Fritz-Haber-Institut der MPG , Faradayweg 4-6, 14195 Berlin, Germany.
authors: Martin
authors: M
authors: Wolf
authors: The Blackett Laboratory, Imperial College London , London SW7 2AZ, United Kingdom.
authors: Vincenzo
authors: V
authors: Giannini
authors: U.S. Naval Research Laboratory , 4555 Overlook Avenue SW, Washington, D.C. 20375, United States.
authors: Joshua D
authors: JD
authors: Caldwell
authors: The Blackett Laboratory, Imperial College London , London SW7 2AZ, United Kingdom.
authors: Stefan A
authors: SA
authors: Maier
authors: Physikalische Chemie, Fritz-Haber-Institut der MPG , Faradayweg 4-6, 14195 Berlin, Germany.
authors: Alexander
authors: A
authors: Paarmann
keywords: Nonlinear optics; nanophononics; polar dielectrics; second harmonic generation; surface phonon polaritons