posted on 2024-01-02, 11:29authored byYanji Yang, Rohit Chikkaraddy, Qianqi Lin, Daniel D. A. Clarke, Daniel Wigger, Jeremy J. Baumberg, Ortwin Hess
The strong-coupling interaction between quantum emitters
and cavities
provides the archetypical platform for fundamental quantum electrodynamics.
Here we show that methylene blue (MB) molecules interact coherently
with subwavelength plasmonic nanocavity modes at room temperature.
Experimental results show that the strong coupling can be switched
on and off reversibly when MB molecules undergo redox reactions which
transform them to leuco-methylene blue molecules. In simulations we
demonstrate the strong coupling between the second excited plasmonic
cavity mode and resonant emitters. However, we also show that other
detuned modes simultaneously couple efficiently to the molecular transitions,
creating unusual cascades of mode spectral shifts and polariton formation.
This is possible due to the relatively large plasmonic particle size
resulting in reduced mode splittings. The results open significant
potential for device applications utilizing active control of strong
coupling.