The generation of correlated photon pairs is a cornerstone in quantum communication since they are useful for quantum-secure data transmission as well as for linking remote quantum systems. In particular for the latter application, photon pair sources with adjustable frequencies can be important since they can provide quantum communication between dissimilar systems. We demonstrate a novel and robust scheme for the generation of correlated photon pairs using spontaneous four-wave mixing in a Fabry-Perot resonator. To this end, we exploit the Kerr nonlinearity of the optical coatings combined with the high finesse of the Fabry-Perot resonator. Our work extends recently emerging studies of nonlinear effects in optical coatings, which so far were limited to ultrashort laser pulses, to the cw domain and, moreover, provides a robust photon pair source utilizing only a continuous-wave diode laser as a pump source.

 

Reference

T.F. Langerfeld, H.M. Meyer, M. Köhl, Physical Review A in press (2018), selected as “Editor’s choice”