The cold-molecule field concerns the physics and the applications of molecular systems with
translational temperature well below the 1 К range. The possibility of controlling all the motion as well
as the internal quantum state of a sample of molecules is a long-term goal that opens the possibility for
many new experiments and measurements ranging from fundamental constants to quantum chemistry
and quantum computation. Although, direct laser cooling of the translational degree of freedom of
molecules is still waiting for further technological or theoretical breakthroughs and ideas, many
different techniques have proven to be successful in producing different types of cold as well as
ultracold (i.e. T < 1 mK) molecules.
In this chapter, we will concentrate on the description of one of these techniques: the photoassociation
of laser cooled atoms. We will report on the status of the art of this technique for the case of cesium
atoms, describing all the main experimental findings. In particular, we will illustrate the different
photoassociation schemes for molecule formation, the detection schemes through photoionization, the
molecule trapping in a magnetic or dipolar trap, the vibrational cooling into a single vibrational state
and finally the present prospects for rotational cooling.
