Source of single correlated photons at 1.06-mkm wavelength

We describe the source of correlated photon pairs at 1.06 micron wavelength based on spontaneous parametric down-conversion. The events corresponding to the photons in the pair are correlated with time accuracy better than 1 ns. Apart from wavelength, another distinctive feature of our set-up is that the “signal” photons can be delayed by passing the additional distance (up to 10 m) in the air.