Regular papers

Dynamics of a chain of optically coupled micro droplets

Laboratoire Ondes et Matière d’Aquitaine, Université Bordeaux I, CNRS, 33405 Talence, France

^* m.perrin@loma.u-bordeaux1.fr

Received: 1 November 2013
Revised: 3 December 2013

Abstract

We study a chain of fluid droplets excited by two incoherent laser beams. Such structured object is merely an array of spherical lenses, that can guide a TEM_pq optical mode. Taking into account the optical forces exerted by two counterpropagating beams, we show that the droplets can be trapped and the chain auto-organizes in the optical potential. The model takes into account the possible coalescence of several droplets, and shows that the droplet size can increase before they become trapped at stable postitions. For some input beam parameters (beam waist size and position), we have observed dynamic trapping : the droplets experience collective oscillation. Meanwhile, the beam shape evolves periodically in time.