Experimental demonstration of small-angle bending in an active direct-coupled chain of spherical microcavities

Abstract

We experimentally demonstrate collective amplified modes along bent chains of directly coupled, amplifying spherical microdroplet resonators. The chains, comprising ∼40 non-contacting resonators, were bent through angles up to ∼25°. The modal probability of the system shows a sharp drop upon bending through small angles (∼10°), and thereafter changes minimally under further bending. The frequency response is significantly maintained under bending. We numerically study the transmittance of a chain of non-contacting amplifying resonators using finite-difference-time-domain calculations, and observe that nanojet filamentation influences coupling at the bend. A self-correcting mechanism of propagation is observed, originating from the lensing effect of the spherical resonator.