Entangling photons using a charged quantum dot in a microcavity

We present two novel schemes to generate photon polarization entanglement via single electron spins confined in charged quantum dots inside microcavities. One scheme is via entangled remote electron spins followed by negatively-charged exciton emissions, and another scheme is via a single electron spin followed by the spin state measurement. Both schemes are based on giant circular birefringence and giant Faraday rotation induced by a single electron spin in a microcavity. Our schemes are deterministic and can generate an arbitrary amount of multi-photon entanglement. Following similar procedures, a scheme for a photon-spin quantum interface is proposed.