Classical light sources with tunable temporal coherence and tailored photon number distributions

Abstract

We demonstrate a method of obtaining, from coherent light, tunable classical light where the temporal characteristics and photon number distribution can be controlled electronically. The tunability of the temporal coherence is shown through second-order correlation (G 2(τ)) measurements, both in the continuous intensity measurement as well as in the photon counting regime. The generation of desired classical photon number distributions is illustrated by creating two light sources —one emitting a thermal state and the other a specific classical non-Gaussian state. Such tailored light sources with emission characteristics quite different from those of existing natural light sources are likely to be useful in quantum information processing, for example, in conjunction with photon addition, to generate tailored non-classical states of light with desired photon number distributions. As a particular application in this direction we also outline how a tailored classical non-Gaussian state generated by our technique may be mixed with a non-classical Gaussian state at a beamsplitter, to generate novel forms of non-Gaussian entanglement.