Photon bunching in parametric down-conversion with continuous-wave excitation
B. Blauensteiner, Isabelle Herbauts, Stefano Bettelli, Andreas Poppe, Hannes Hübel · Physical Review A · 2009
Direct measurement of photon bunching (${g}_{(2)}$ correlation function) in one output arm of a spontaneous-parametric-down-conversion source operated with a continuous pump laser in the single-photon regime is demonstrated. The result is in agreement with the statistics of a thermal field of the same coherence length and shows the feasibility of investigating photon statistics with compact continuous-wave-pumped sources. Implications for entanglement-based quantum cryptography are discussed.