Аннотация

Organic microresonators are highly attractive for numerous applications including biosensing,optical switching and metrology. Adding chiral materials to resonators can enhance theirsensing properties due to the appearance of chiroptical effects. Here we study experimentallyresonant multiphoton processes in spherical microresonators with the diameter of 2–12 μmmade of 1,1’-bi-2-naphthol derivatives by a self-assembly technique. Using nonlinear singleparticlemicroscopy, we demonstrate that these microspheres provide excitation of whisperinggallery modes (WGMs) in two- and three-photon excited luminescence with a Q-factor ofup to 300. We also demonstrate that the nonlinear circular dichroism is enhanced due tothe WGM excitation and reaches 7.7% and 11% in the two- and three-photon absorption,respectively. Pronounced modulation of the WGMs spectrum due to the mode’s splitting isobserved in coupled binol-based microresonators, which opens a path for the control over theirresonant response and makes them suitable for nonlinear optical sensing applications.