Anticorrelation effect in femtosecond-pulse pumped type-II spontaneous parametric down-conversion

Abstract

We report an experimental demonstration of an anticorrelation effect in femtosecond-pulse pumped type-II spontaneous parametric down-conversion. Our experimental data, which is different from that of Atat\ure et al. [Phys. Rev. Lett. 83, 1323 (2000)], confirmed the shallow symmetric ``dip'' that is predicted theoretically by Keller and Rubin [Phys. Rev. A 56, 1534 (1997)] and Grice and Walmsley [Phys. Rev. A 56, 1627 (1997)]. We show in this paper that the asymmetric dip observed in the literature is an artifact, which is caused by the asymmetric optical elements introduced into the beam path after the down-conversion process. The ``partial distinguishability'' theory suggested by Atat\ure et al. is therefore incorrect.