Optics Express
Second order coherence of broadband down-converted light on ultrashort time scale determined by two photon absorption in semiconductor
Fabien Boitier, Antoine Godard, Aleksandr I. Ryasnyanskiy, N. Dubreuil, Philippe Delaye, Claude Fabre, E. Rosencher
Abstract
We study the photon correlation properties of broadband parametric down-converted light. The measurement of the photon correlation is carried out thanks to a modified Hanbury Brown-Twiss interferometer based on two photon absorption in GaAs detector. Since this method is not affected by the phase matching conditions of the detecting apparatus (so called "final state post-selection"), the detection bandwidth can be extremely large. This is illustrated by studying, with the same apparatus, the degree of second order coherence of parametric light in both degenerate and non-degenerate cases. We show that our experiment is able to determine the coherent as well as the incoherent contributions to the degree of second order coherence of parametric light with a time resolution in the fs range scale.