Physics

Dr. Rohit Chikkaraddy
Cavendish Lab, University of Cambridge

Abstract: Complete mixing of energy states of molecules and light provides profound effects in quantum optics and photochemistry. Achieving these mixed states with visible light at the single-molecule level is severely hindered by the conflict between the molecular homogeneous linewidth and the low quality factor of the necessary ultra-small photonic cavities. In this talk, I will present how sub-nm gaps between the metallic structure generate intense local field amplification with mode volumes <100nm^3 [1,2]. Individual molecules that are precisely positioned and oriented into these local fields using guest-host supramolecular chemistry [2] and DNA origami [3] leads to strongly mixed states of light and matter states with coupling strength exceeding the losses of the system[2,4]. Further, the non-classical light emission from the molecule is strongly modulated by the influence of vibrational relaxation on the Jaynes-Cummings ladder [5,6]. These results show that cavity quantum electrodynamic effects can be observed in molecular systems at ambient conditions, opening significant potential for new devises and light controlled reaction pathway.

References:

[1] R. Chikkaraddy et al, ACS Photonics 4 (2017) 469–475;
[2] R. Chikkaraddy et al., Nature 535 (2016) 127–130;
[3] R. Chikkaraddy et al., Nano Letters 18 (2018) 405-411;
[4] M.-E. Kleemann, R. Chikkaraddy et al., Nat Commun 8 (2017) 1296;
[5] F. Benz, M.K. Schmidt, A. Dreismann, R. Chikkaraddy et al., Science 354 (2016) 726–729;
[6] O. S. Ojambati, R. Chikkaraddy et al., Submitted (2018);