Near-field optical trapping with an actively locked cavity

N J van Leeuwen, L J Moore, W D Partridge, R Peverall, G A D Ritchie and M D Summers

This paper details the construction and performance of a resonant cavity evanescent wave trap for the trapping and assembling of microparticles. The technique employs a low finesse resonator which incorporates total internal reflection (TIR) at the silica/water interface to generate an evanescent field which is coherently scattered by silica microparticles present in suspension to form optically bound structures. Circulating powers of 14 W over an area of 150 µm × 75 µm were generated with a 400 mW Nd:YAG source. This approach allows some degree of control over the shape of the evanescent field by locking to higher-order cavity modes.

DOI