ausblenden:
Schlagwörter:
-
Zusammenfassung:
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.
