Purcell-enhanced spontaneous emission of molecular vibrations

Reviews and Highlights	Quantum Science	Molecular and Soft-matter	Ultrafast Nano-optics and Nanophotonics	Mineralogy and Geochemistry

Bernd Metzger, Eric Muller, Jun Nishida, Benjamin Pollard, Mario Hentschel, and Markus B. Raschke
Phys. Rev. Lett. 123, 153001 (2019).
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Infrared (IR) spectroscopy of molecular vibrations provides insight into molecular structure, coupling, and dynamics. However, picosecond scale intermolecular and intramolecular many-body interactions, nonradiative relaxation, absorption, and thermalization typically dominate over IR spontaneous emission. We demonstrate how coupling to a resonant IR antenna can enhance spontaneous emission of molecular vibratio{“type”:”block”,”srcIndex”:4,”srcClientId”:”96a65832-8136-4cf1-bbbf-9949686d1837″,”srcRootClientId”:””}ns. Using time-domain nanoprobe spectroscopy we observe an up to 50% decrease in vibrational dephasing time T_2,vib, based on the coupling-induced population decay with T_κ≃550fs and an associated Purcell factor of >10⁶. This rate enhancement of the spontaneous emission of antenna-coupled molecular vibrations opens new avenues for IR coherent control, quantum information processing, and quantum chemistry.