Polarization entanglement restored in solid-state photon sources

Ismail Nassar, Dan Cogan, and Ido Schwartz of the Technion-Israel Institute of Technology have demonstrated a method to restore polarization entanglement in photons emitted from a semiconductor quantum dot. The researchers applied synchronized, time-dependent operations directly to emitted photons, reversing accumulated phase shifts caused by internal dynamics within the quantum dot itself. This photonic-compensation protocol recovers entanglement without needing to filter data based on emission time or relying on precise detector timing. The work establishes a strategy for removing the impact of emitter dynamics on photonic entanglement. Using exciton fine-structure splitting of 8.80 ± 0.04 microelectronvolts in a semiconductor quantum dot as a…