Date: Friday April 15, 2011
Time: 11:00
Place: ETH Science City, 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)