Light induced trapping potential for neutral atoms by mode interference of a blue detuned light field in ultra thin fibres

Nicholas Sullivan, Shira Jackson, ByungChan Ha +1 more

G. Sagué, Alexander Baade, Arno Rauschenbeutel

We present and analyse a novel concept for blue-detuned evanescent field surface traps for cold neutral atoms based on two-mode interference in ultrathin optical fibres. When two or more transverse modes with the same frequency co-propagate in the fibre, their different phase velocities cause a stationary interference pattern to establish. Intensity minima of the evanescent field at any distance from the surface can be created and an array of optical microtraps can thus be obtained around the fibre. We discuss three possible combinations of the lowest order modes, yielding traps at 100–200 nm from the fibre surface which, using a few tens of milliwatts of trapping laser power, have a depth of the order of 1 mK for caesium atoms and a trapping lifetime exceeding 100 s. The resulting trapping geometry is of particular interest because atoms in such microtrap arrays will be coupled to any additional field propagating in the fibre via the evanescent field, thereby realizing ensembles of fibre-coupled atoms.

zhao chen, Qi Zhang, Fan Zhang +2 more

We have theoretically demonstrated the atom trapping based on periodic ring nanocavities by circular blue-detuned light. A three-dimensional trapping potential are achieved with ultra-low optical power, scattering rate and large trapping lifetime.

Harold J. Metcalf, P. van der Straten

Jean Dalibard, Serge Reynaud, Claude N. Cohen-Tannoudji

C. F. Phelan, Tara Hennessy, Thomas Busch

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 HE(21) mode. Counter propagating red-detuned HE(21) modes are combined with a blue-detuned HE(11) fundamental mode to form a potential in the shape of four intertwined spirals. By changing the polarization from circular to linear in each of the two counter-propagating HE(21) 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 TE(01) and TM(01) modes is also discussed.