Photoionization spectroscopy of excited states of cold caesium dimers

Photoionization spectroscopy of cold caesium dimers obtained by photoassociation of cold atoms in a magnetooptical trap is reported here. In particular, we report on the observation and on the spectroscopic analysis of all the excited states that have actually been used for efficient detection of cold molecules stabilized in the triplet a3Sigmau ground state. They are: the (1)3Sigmag state connected to the 6s+6p asymptote, the (2)3Sigmag and (2)3Pig states onnected to the 6s+5d asymptote and finally the (3)3Sigmag state connected to the 6s+7s asymptote. The detection through these states spans a wide range of laser energies, from 8000 to 16,500 cm-1, obtained with different laser dyes and techniques. Information on the initial distribution of cold molecules among the different vibrational levels of the a3Sigmau ground state is also provided. This spectroscopic knowledge is important when conceiving schemes for quantum manipulation, population transfer and optical detection of cold caesium molecules.