Integrating cold atoms into optical waveguides

Shengwang Du

Manuel Succo

This thesis introduces the first demonstration of a monolithic, micro-fabricated, multi-channel, optical-waveguide chip to measure ultra-cold atomic clouds. The optics consist of an array of 12 independent junctions, which are separated by only 10 μm and have large atom-photon coupling. The integrated and scalable design is presented, along with an atom chip for mounting the optical waveguide chip and magnetically trapping and handling ultra-cold atoms. The experimental apparatus which was built to accommodate this new chip set is described, along with a new experimental control programme which was developed to accommodate the scalability requirements of the new chip. The chip was optically, mechanically and magnetically characterised and cold atoms with densities up to 10-² μm-³, corresponding to 1 atom at a time inside the waveguide mode, were detected with this new kind of chip using absorption and fluorescence techniques. Subsequently, the atoms were utilised to diagnose light polarisation and intensity within the optical-waveguide chip. For future use, various detection methods adapted to the optical-waveguide chip were considered to minimise photon scattering and thus heating of a trapped ultra-cold sample of atoms.

Nicholas J. Karl, Michael R. Gehl, William Kindel +10 more

We demonstrate an optical waveguide device capable of supporting the optical power necessary for trapping a single atom or a cold-atom ensemble with evanescent fields. Our photonic integrated platform successfully manages optical powers of ~30mW.

E. Giacobino, Jean-Michel Courty, Claude Fabre +2 more

M. L. Miguez, Ph. W. Courteille

J Lee, D H Park, S Mittal +2 more

An integrated optical dipole trap uses two-color (red and blue-detuned) traveling evanescent wave fields for trapping cold neutral atoms. To achieve longitudinal confinement, we propose using an integrated optical waveguide coupler, which provides a potential gradient along the beam propagation direction sufficient to confine atoms. This integrated optical dipole trap can support an atomic ensemble with a large optical depth due to its small mode area. Its quasi- TE 0 waveguide mode has an advantage over the HE 11 mode of a nanofiber, with little inhomogeneous Zeeman broadening at the trapping region. The longitudinal confinement eliminates the need for a one dimensional optical lattice, reducing collisional blockaded atomic loading, potentially producing larger ensembles. The waveguide trap allows for scalability and integrability with nano-fabrication technology. We analyze the potential performance of such integrated atom traps.