Trapping of single nano-objects in dynamic temperature fields

Marco Braun (1) , Frank Cichos (1) , Alois Würger (2)

1 Institut für Experimentalphysik [Innsbruck]
2 LOMA - Laboratoire Ondes et Matière d'Aquitaine

In this article we explore the dynamics of a Brownian particle in a feedback-free dynamic thermophoretic trap. The trap contains a focused laser beam heating a circular gold structure locally and creating a repulsive thermal potential for a Brownian particle. In order to confine a particle the heating beam is steered along the circumference of the gold structure leading to a non-trivial motion of the particle. We theoretically find a stability condition by switching to a rotating frame, where the laser beam is at rest. Particle trajectories and stable points are calculated as a function of the laser rotation frequency and are experimentally confirmed. Additionally, the effect of Brownian motion is considered. The present study complements the dynamic thermophoretic trapping with a theoretical basis and will enhance the applicability in micro- and nanofluidic devices.

Domaines: Matière Molle [cond-mat.soft]

Marco Braun, Frank Cichos, Alois Würger. Trapping of single nano-objects in dynamic temperature fields. Physical Chemistry Chemical Physics, 2014, 16, pp.15207. ⟨10.1039/c4cp01560f⟩. ⟨hal-01025336⟩