Stuttgart 2012 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 17: Kalte Atome: Fallen und Kühlung

Q 17.4: Vortrag

Montag, 12. März 2012, 17:15–17:30, V7.02

Creating atom-number states around tapered optical fibres by loading from an optical lattice — •Tara Hennessy and Thomas Busch — University College Cork, Republic of Ireland

We present a scheme where the evanescent field around a sub-wavelength diameter tapered nanofibre is combined with the periodic potential of an optical lattice. We show that when the fibre is aligned perpendicularly to the transverse plane of a two-dimensional optical lattice the evanescent field around the fibre can be used to create a time-dependent potential which locally melts the lattice potential.

We first describe the disturbance of the lattice due to scattering of the lattice beams on the fibre, then show how the attractive van der Waals potential close to the surface can be compensated by a blue-detuned evanescent field and finally characterise the resulting atomic samples in the melted part of the lattice. This scheme allows access to a regime in which a small number of particles can be addressed locally without disturbing the rest of the lattice. Furthermore, if the environment around the fibre is given by a well ordered Mott-Insulator state, the melting of the lattice transfers a controllable and well-defined number of atoms from the individual lattice sites around the fibre into the fibre potential. The resulting state is therefore number squeezed and can be used for applications in quantum information or metrology.