Shaping the evanescent field of optical nanofibers for cold atom trapping


Abstract in English

We investigate trapping geometries for cold, neutral atoms that can be created in the evanescent field of a tapered optical fibre by combining the fundamental mode with one of the next lowest possible modes, namely the HE21 mode. Counter propagating red-detuned HE21 modes are combined with a blue-detuned HE11 fundamental mode to form a potential in the shape of four intertwined spirals. By changing the polar- ization from circular to linear in each of the two counter-propagating HE21 modes simultaneously the 4-helix configuration can be transformed into a lattice configuration. The modification to the 4-helix configuration due to unwanted excitation of the the T E01 and T M01 modes is also discussed.

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