Nanoimaging and Control of Molecular Vibrations throughElectromagnetically Induced Scattering Reaching the Strong CouplingRegime

摘要

Optical resonators can enhance light–matter interaction, modify intrinsic molecular properties such as radiative emission rates, and create new molecule–photon hybrid quantum states. To date, corresponding implementations are based on electronic transitions in the visible spectral region with large transition dipoles yet hampered by fast femtosecond electronic dephasing. In contrast, coupling molecular vibrations with their weaker dipoles to infrared optical resonators has been less explored, despite long-lived coherences with 2 orders of magnitude longer dephasing times. Here, we achieve excitation of molecular vibrations through configurable optical interactions of a nanotip with an infrared resonant nanowire that supports tunable bright and nonradiative dark modes. The resulting antenna–vibrational coupling up to 47 ± 5 cm^–1 exceeds the intrinsic dephasing rate of the molecular vibration, leading to hybridization and mode splitting. We observe nanotip-induced quantum interference of vibrational excitation pathways in spectroscopic nanoimaging, whichwe model classically as plasmonic electromagnetically induced scatteringas the phase-controlled extension of the classical analogue of electromagneticallyinduced transparency and absorption. Our results present a new regimeof IR spectroscopy for applications of vibrational coherence fromquantum computing to optical control of chemical reactions.