Generation of bright visible photon pairs using a periodically poled stoichiometric lithium tantalate crystal.

We demonstrate a 711-nm-wavelength efficient photon-pair source under the condition of non-collinear type-0 quasi-phase-matching configuration in a periodically poled MgO-doped stoichiometric lithium tantalate (PPSLT) crystal pumped by a 355.7-nm laser. Such degenerate visible photon-pairs in the wavelength region of 710 nm are practically useful for increasing the data collection rate in silicon-based single photon detectors. We confirm that the visible photon pairs in the PPSLT crystal form a bright, high-purity source of correlated photons. Our results show a coincidence counting rate per input pump power of 98,500 Hz/mW, conversion efficiency of 1.66 × 10^-9, and second-order coherence function g⁽²⁾(0) of 0.087 ± 0.002/mW.