Tunable quantum interference of single photons using nonlinear nanophotonics

In Physical Review Applied, we report on using nonlinear nanophotonics to realize the tunable quantum interference of single photons (https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.12.054054).  The two non-degenerate (different in color) photons that comprise a photon-pair source created on one nanophotonic chip are made identical through quantum frequency conversion realized through a second nanophotonic chip.  The photons are then interfered to show that they have been made identical.