Author: ["F. Boitier","A. Godard","E. Rosencher","C. Fabre"]
CITE.CC academic search helps you expand the influence of your papers.
Abstract
Although the bunching of photons emitted from an incoherent source is well known, this has only ever been measured down to a temporal resolution of nanoseconds. This has now been improved by many orders of magnitude to the level of femtoseconds, with the elegantly simple use of a GaAs two-photon detector. Photon beams exhibit temporal correlations that are characteristics of their emission mechanism. For instance, photons issued from incoherent sources tend to be detected in bunches. This striking ‘bunching’ behaviour has been observed in the seminal experiment by Hanbury-Brown and Twiss (HBT) in the fifties, who measured the time of arrival of partially coherent photons on two separate photon-counting modules1. Since then, HBT interferometry has become a widespread technique to study photon correlations down to only the nanosecond range, because of the detector-limited bandwidth, preventing the observation of bunching for real thermal sources. It has been suggested later that two-photon absorption (TPA) could measure the photon temporal correlations at a much shorter timescale2,3, as it involves an almost simultaneous absorption of two photons, within a maximum delay given by the Heisenberg principle. Here, for the first time, this prediction is experimentally demonstrated using TPA in a GaAs photon-counting module. We have observed photon bunching in the femtosecond range for real blackbody sources (an enhancement of six orders of magnitude in the time resolution of present techniques), opening the way to monitor optical quantum statistics at the ultrashort timescale.Cite this article
Boitier, F., Godard, A., Rosencher, E. et al. Measuring photon bunching at ultrashort timescale by two-photon absorption in semiconductors. Nature Phys 5, 267–270 (2009). https://doi.org/10.1038/nphys1218 