  We perform a stability analysis of superfluid (SF) and supersolid (SS) phases
of polarized dipolar bosons in two-dimensional optical lattices at high filling
factors and zero temperature, and obtain the phase boundaries between SF,
checkerboard SS (CSS), striped SS (SSS), and collapse. We show that the phase
diagram can be explored through the application of an external field and the
tuning of its direction with respect to the optical lattice plane. In
particular, we find a transition between the CSS and SSS phases.
