  We study the generation of entangled light in planar semiconductor
microcavities. The focus is on a particular pump configuration where the
dissipative internal polariton dynamics leads to the emission of entangled
light in a W-state. Our study is based on the nonlinear equations of motion for
the polariton operators derived within the dynamics-controlled truncation
formalism. They include the losses through the cavity mirrors, the interaction
with lattice vibrations, and the external laser driving in a Langevin approach.
We find that the generated entanglement is robust against decoherence under
realistic experimental conditions. The results show that pair correlations in
solid-state devices can be used to stabilize the nonlocal properties of the
emitted radiation.
