Nyman, Robert A.

Friday April 15, 2011
Time: 11:00
Place: HPF G 6
Host: Tilman Esslinger

An Integrated Photonic Atom Chip and Minimally-Destructive Detection of Magnetically-Trapped Atoms

Robert A. Nyman
Imperial College, London, UK

We have constructed a new kind of atom chip using integrated optical waveguides, combined with structures for magnetic trapping. There are 12 buried, single-mode optical waveguides in doped silica, cut across by a trench. We detect low-density samples of laser-cooled rubidium atoms launched into the trench, by measuring the absorption of light[1]. Conversely, we have used the atoms to probe the intensity and polarisation of the light carried by the waveguides.
We have also developed a two-frequency interferometer to measure atomic density in a magnetic trap more than 100 times on a single sample[2]. We achieve statistically-limited phase noise down to 5800 detected photons in 10 microsecond. Atomic loss rates fit a simple rate model of photon scattering, and can be combined with the phase response to form a figure of merit to optimise the detection system: the more photons  used, the more sensitive the measurement, but the greater the loss. Smaller beams make for better detection with less loss, hence the interest in integrating the microfabricated photonic chip.

[1] M. Kohnen et al., Nature Photonics vol.5, p35 (2011).
[2] M. Kohnen et al., arXiv:1104.0236 (2011)