Fig. 1: Light-matter interaction in an azopyrrole photoswitch.

a Molecular structure and photoisomerization reaction of azopyrrole; b absorption spectra of E and Z-isomers of azopyrrole derivative in a polymethyl methacrylate (PMMA) matrix; c Schematic of energy diagram showing the collective coupling of E and Z-isomers with a cavity mode and the collapse of Rabi splitting energy upon irradiation. Dark states are also shown for clarity. (The relative population difference in E and Z-isomers is exaggerated).