Year: 2017
Type: article
Abstract: Mid-infrared nanophotonics can be realized using subdiffractional light localization and field enhancement with surface phonon polaritons in polar dielectric materials. We experimentally demonstrate second-harmonic generation due to the optical field enhancement from critically coupled surface phonon polaritons at the 6H-SiC–air interface, employing an infrared free-electron laser for intense, tunable, and narrowband mid-infrared excitation. Critical coupling to the surface polaritons is achieved using a prism in the Otto geometry with adjustable width of the air gap, providing a contact-free access to the polariton dispersion with full control over the excitation conditions. The calculated reflectivity and second-harmonic spectra reproduce the complete experimental data set with high accuracy, allowing for a quantification of the optical field enhancement. We also reveal the mechanism for low out-coupling efficiency of the second-harmonic light in the Otto geometry. Perspectives on surface phonon polariton-based nonlinear sensing and nonlinear waveguide coupling are discussed.
Source: ACS Photonics
Authors: Nikolai Christian Passler, Ilya Razdolski, Sandy Gewinner, Wieland Schöllkopf, Martin Wolf, Alexander Paarmann
Institution: Fritz Haber Institute of the Max Planck Society
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2606302149