Near-field optical manipulation with cavity enhanced evanescent fields

In the following paper we show that near-field optical manipulation can be greatly increased through the use of cavity enhanced evanescent fields. This approach utilises a resonant dielectric structure and a prism coupler to produce Fabry- Perot like cavity modes at a dielectric-fluid interface, which can be utilised in optical manipulation. Using this structure we show a ten-times increase in the optical interaction of micrometer-sized colloids compared with the standard evanescent wave configuration. In addition, stable accumulation and ordering of large-scale arrays of colloids is demonstrated using two counter propagating cavity enhanced evanescent fields. We believe that this technique has considerable scope for promoting the role of near-field optical manipulation at the nanometer scale.