Signatures of the Optical Stark Effect on Entangled Photon Pairs from Resonantly-Pumped Quantum Dots

Abstract

Two-photon resonant excitation of the biexciton-exciton cascade in a quantum dot generates highly polarization-entangled photon pairs in a near-deterministic way. However, there are still open questions on the ultimate level of achievable entanglement. Here, we observe the impact of the laser-induced AC-Stark effect on the spectral emission features and on entanglement. A shorter emission time, longer laser pulse duration, and higher pump power all result in lower values of concurrence. Nonetheless, additional contributions are still required to fully account for the observed below-unity concurrence.Comment: 7 pages, 3 figure