Optimizing the photoassociation of cold atoms by use of chirped laser pulses

Photoassociation of ultracold atoms induced by chirped picosecond pulses is analyzed in a nonperturbative treatment by following the wavepackets dynamics on the ground and excited surfaces. The initial state is described by a Boltzmann distribution of continuum scattering states. The chosen example is photoassociation of cesium atoms at temperature T=54 μK from the aΣ u (6s, 6s) continuum to bound levels in the external well of the 0g (6s + 6p3/2) potential. We study how the modification of the pulse characteristics (carrier frequency, duration, linear chirp rate and intensity) can enhance the number of photoassociated molecules and suggest ways of optimizing the production of stable molecules. PACS. 33.80.Ps Optical cooling of molecules; trapping; 33.80 -b Photon interactions with molecules 33.90 +h New topics in molecular properties, interaction with photons 33.80.Gj diffuse spectra; predissociation,