Photoionization spectroscopy of excited states of cold cesium dimers

Photoionization spectroscopy of cold cesium dimers obtained by photoassociation of cold atoms in a magneto-optical 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 a^3Sigma_u^+ ground state. They are: the (1)^3Sigma_g^+ state connected to the 6s+6p asymptote, the (2)^3Sigma_g^+ and (2)^3Pi_g states connected to the 6s+5d asymptote and finally the (3)^3Sigma_g^+ state connected to the 6s + 7s asymptote. The detection through these states spans a wide range of laser energies, from 8000 to 16500 cm-1, obtained with different laser dyes and techniques. Information on the initial distribution of cold molecules among the different vibrational levels of the a^3Sigma_u^+ ground state is also provided. This spectroscopic knowledge is important when conceiving schemes for quantum manipulation, population transfer and optical detection of cold cesium molecules.