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Restoring Dispersion Cancellation for Entangled Photons Produced by Ultrashort Pulses



R Erdmann, D A. Branning, W P. Grice, L A. Walmsley


It is a well-known and remarkable fact that in certain coincidence photon counting experiments with cw-pumped parametric downconverters, the effects of group velocity dispersion arising from media interposed between source and detectors are completely cancelled, even if the media physically affect only one of the photons of the pair. Recently Perina et al (1999) showed that this phenomenon does not occur when certain classical timing information is available about the arrival of individual photons at the detectors, as is the case when the photon pairs are produced via spontaneous parametric downconversion using an ultrashort pump pulse.In this paper, we show that that the nonlocal cancellation of dispersion for such a source of entangled photons can be restored in principle by proper engineering of the source properties. In particular we describe techniques for recovering interference in coincidence counting experiments by suppressing distinguishing information without post selection of photons. Moreover, a precise classical timing signal coincident with the photon pair is still available.
Physical Review A (Atomic, Molecular and Optical Physics)
No. 5


dispersion, entangled states, optical delay, parametric down conversion, quantum interference, two-photons


Erdmann, R. , Branning, D. , Grice, W. and Walmsley, L. (2000), Restoring Dispersion Cancellation for Entangled Photons Produced by Ultrashort Pulses, Physical Review A (Atomic, Molecular and Optical Physics) (Accessed April 18, 2024)
Created October 31, 2000, Updated October 12, 2021