Large light-assisted collision rates between cold atoms in a microscopic dipole trap

We study light-assisted collisions in an ensemble containing a small number (~3) of cold Rb87 atoms trapped in a microscopic dipole trap. We measure the loss rates due to the light-induced heating of the atoms (one-body loss mechanism) and to the light-assisted collisions (two-body loss mechanism) when we send a near-resonant laser excitation. Our measurements indicate that the two-body loss rate can reach remarkably large values beta > 10^{-8} cm^3.s^{-1} and varies rapidly with the trap depth and the parameters of the excitation light.