Reversible switching of ultrastrong light-molecule coupling

Phys Rev Lett. 2011 May 13;106(19):196405. doi: 10.1103/PhysRevLett.106.196405. Epub 2011 May 11.


We demonstrate that photochromic molecules enable switching from the weak- to ultrastrong-coupling regime reversibly, by using all-optical control. This switch is achieved by photochemically inducing conformational changes in the molecule. Remarkably, a Rabi splitting of 700 meV is measured at room temperature, corresponding to 32% of the molecular transition energy. A similar coupling strength is demonstrated in a plasmonic structure. Such systems present a unique combination of coupling strength and functional capacities.