Semi-empirical Quantum Optics for Mid-Infrared Molecular Nanophotonics

Nanoscale infrared resonators with sub-diffraction mode volumes are new platforms for implementing cavity QED at room temperature. Infrared nano-antennas and tip probes are ideal for studying vibrational strong coupling and for implenting quantum control schemes with nanometer and femtosecond resolution. We develop a general semi-empirical quantum optics approach to describe vibration-tip-antenna interactions under femtosecond laser driving [1]. The theory reproduces recent experiments on the acceleration of the vibrational relaxation rate in nanostructures and gives physical insights for the implementation of coherent phase rotations of the near-field using broadband nanotips. We apply the quantum framework to construct tip-design rules for the experimental manipulation of vibrational strong coupling and Fano interference effects in open infrared resonators, and propose a feasible scheme for transfering the anharmonicity of molecular vibrations to the resonator near-field in weak coupling for implementing nonlinear phase shifts in the coupled infrared response of the system. Our work can facilitate the rapid design of infrared nanophotonic hardware for applications in quantum control of materials, infrared quantum metrology, and quantum information processing [2-5].