  We consider the formation of cold ground-state polar molecules in a low
vibrational level by laser fields. Starting from a pair of cold colliding atoms
of dissimilar species, we propose a strategy consisting of three steps. In the
first step, a pump pulse induces the molecule formation by photoassociating the
atomic pair in a high or intermediate vibrational level of an excited
electronic molecular state. This step is followed by a dump pulse in an
intermediate vibrational level of the ground state. In the last step, an
infrared chirped pulse induces downward transitions among the vibrational
levels of the ground electronic state, reaching the ground vibrational level.
Initially, the strategy is constructed with fixed-shaped pulses. Subsequently,
we perform the calculations with optimized chirped pulses introducing an
optimal control technique in which the optimization of the time-dependent
frequency is carried out in the time domain. The proposed scheme is an
alternative to the use of two pairs of pump-dump pulses or to the direct
photoassociation and vibrational stabilization in the ground state.
