Professor Christopher Foot

Abstract:

The realization of Bose-Einstein condensation of 133Cs relies on an innovative evaporative cooling technique using a dimple potential. Correctly loading an atomic gas into such a potential produces a dense sample with a high phase space density, ideal for evaporative cooling. We have numerically simulated both the loading process and the subsequent evaporative cooling from a dimple potential in order to elucidate the optimization of this technique. Furthermore, we demonstrate that this technique would be effective in cooling 85Rb to quantum degeneracy and describe a simple scheme for its implementation.

Abstract:

Trapping and manipulation of cold atoms using optical potentials require the ability to generate and control a time varying light intensity distribution. Such an application demands that fast changing intensity distributions are generated, which are however free from flickering, or noise in general. Ferroelectric spatial light modulators are good candidates to achieve this because of their high refresh rate but they suffer from noise due to changes in the state of individual pixels during an animated sequence. A direct binary search based optimization routine was developed which minimizes the noise during such sequences. Filter sequences designed using this technique have been tested experimentally and the results demonstrated that flicker noise was eliminated. © 2004 Taylor & Francis Group, LLC.