Tim J. Bartley, National Institute of Standards and Technology, Boulder
Fundamental to quantum optics is the study of the distribution of photons in modes of an electromagnetic field. Until now, direct photon number measurements on nonclassical states occupying a single mode have been limited to the few-photon regime (typically no more than 5). I will present results from direct measurements of nonclassical states containing up to 50 (fifty) photons, at telecom wavelengths and with total raw efficiencies well above 60%. Additionally, I will introduce theoretical work on an alternative route to generate large nonclassical states. This approach uses a pair of single photons to entangle two independent (and arbitrarily large) coherent states. The joint photon-number statistics of this state have some interesting properties. I will introduce the notion of “discorrelation,” which, in contrast to correlated states, encapsulates how measurements of photon number on each mode of this state never yield the same outcome. This extends the lack of coincident measurements of single photons in a Hong-Ou-Mandel experiment to a higher-dimensional photon-number space.