Interaction of colloids with laser-induced external fields

Participants: Erick Sarmiento, José Luis Arauz

A two laser beam interferometer produces an interference pattern of fringes, with a sinusoidal shape. Due to reflection in the surface of a dielectric particle, Brownian particles are attracted to the high intensity regions, thus acting as an external field. The periodicity and intensity of this external field can be varied easily with optical components.

Additional to this external field, Brownian particles interact among themselves by direct (electrostatic, dipolar...) or indirect (hydrodynamic) interactions. We are currently exploring the effects of this external periodic field in the Brownian motion of anisotropic particles (dumbbells). By using spherical particles with a conductive core that produces a dipolar interaction between themselves, we are also exploring the competition between direct interaction and external interaction. Additionally, light laser field can produce confinement, thus providing an effective way to induce crystallization.

Last Uptade: January 2015