Dresden 2011 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 5: Ultracold Atoms: Manipulation and Detection
Q 5.9: Talk
Monday, March 14, 2011, 12:30–12:45, SCH 251
Improved detection of small atom numbers through image processing — •Caspar Ockeloen1,2, Atreju Tauschinksy1, Robert Spreeuw1, and Shannon Whitlock1,3 — 1University of Amsterdam, The Netherlands — 2Universität Basel, Switzerland — 3Universität Heidelberg, Germany
We demonstrate improved detection of small trapped atomic ensembles through advanced post-processing and optimal analysis of absorption images. These techniques provide the basis to improve the readout of trapped atom interferometers to the quantum limit or to better resolve number/spin-squeezing and entanglement between small atomic ensembles. A fringe removal algorithm reduces imaging noise to the fundamental photon-shot-noise level and proves beneficial even in the absence of fringes. A maximum-likelihood estimator is then derived for optimal atom-number estimation and is applied to real experimental data to measure the population differences and intrinsic atom shot-noise between spatially separated ensembles each comprising between 10 and 2000 atoms. The combined techniques improve our signal-to-noise by a factor of 3, to a minimum resolvable population difference of 17 atoms, close to our ultimate detection limit.