  Radiative two-photon cascades from biexcitons in semiconductor quantum dots
under resonant two-photon excitation are promising candidates for the
generation of photon pairs. In this work, we propose a scheme to obtain
two-photon emission that allows to operate under very intense driving fields.
This approach relies on the Purcell enhancement of two-photon virtual
transitions between states of the biexciton dressed by the laser. The richness
provided by the biexcitonic level structure allows to reach a variety of
regimes, from antibunched and bunched photon pairs with polarization orthogonal
to the driving field, to polarization entangled two-photon emission. This
evidences that the general paradigm of two-photon emission from a ladder of
dressed states can find interesting, particular implementations in a variety of
systems.
