AtMol Research Seminar Archive
Index Current Seminars

Summer 2008

Date Speaker Institution
Realisation of a Cold Mixture of Rubidium and Caesium: A PhD review
July 9th Dr. Margaret Harris Institute of Physics

'A new apparatus designed to study cold, ultracold, and quantum degenerate mixtures of rudidium and caesium atoms is described. The Rb-Cs mixture is prepared using a double magneto-optical trap (MOT) system in which a two-species pyramid MOT acts as a source of cold atoms for a 'science' MOT. The results of experiments on the magneto-optically trapped mixture are presented, including measurements of trap loss rates due to single-species and interspecies inelastic collisions. A technique for reducing interspecies loss by spatially separating the MOTs during loading is described. The displaced MOT offers great flexibility in the ratios of Rb and Cs available for loading into magnetic or optical traps, and thus provides an excellent starting point for future work.

A model of polarisation spectroscopy based on numerical integration of population rate equations is also presented. Theoretical polarisation spectra generated for the F=I+1/2 --> F' transitions in Rb and Cs are shown to agree with experimental spectra. An investigation of the sub-Doppler DAVLL technique demonstrates how locking signals can be optimised for the Rb D2 transitions. Comparisons between polarisation spectroscopy and DAVLL are used to enhance understanding of atom-light interactions and indicate methods for optimising lock signals in cold atom experiments.

Venue: James Knott Library

CPT in an open atomic system with spatially separated pump and probe laser beam
August 13th Dr. Brana Jelenkovic Institute of Physics, Belgrade

His research interests are in the fields of Quantum and non-linear optics, laser spectroscopy, optical metrology, optical sensors. Very recently he has been working on electromagnetically induced transmission and absorption.

Vortex Formation and Interference Properties of Merging BECs
August 27th Mr. Bo Xiong Nottingham University

Nonlinear excitations, like solitons and vortices in Bose-Einstein condensates (BECs) of trapped cold atoms have been observed in some experiments. There has recently been a particular focus on the creation of these excitations merging, interfering or reflecting BECs. In this talk, the inherent connection between vortex formation and interference in merging BECs will be shown, which explains some experimental phenomena. The effects of interactions on the interference properties of merging condensates will be shown, particularly essential relations for the interference patterns produced respectively by colliding, expanding and merging condensates. If time permits, I will show some recent work around these regimes in the Cold Atom Group of Nottingham.