Optics Letters, Vol. 40, Issue 6, pp. 922-925 (2015)
Spotlight on Optics March 2015
Philip J. Bustard, Jennifer Erskine, Duncan G. England, Josh Nunn, Paul Hockett, Rune Lausten, Michael Spanner, and Benjamin J. Sussman
Quantum photonics offers much promise for the development of new technologies. The ability to control the interaction of light and matter at the level of single quantum excitations is a prerequisite for the construction of potentially powerful devices. Here we use the rotational levels of a room temperature ensemble of hydrogen molecules to couple two distinct optical modes at the single photon level using femtosecond pulses with 2 THz bandwidth. We observe photon correlations that violate a Cauchy–Schwarz inequality, thereby verifying the creation of a nonclassical state. This work demonstrates the rich potential of molecules for use in ultrafast quantum photonic devices.