Some Coherence Properties of Non-Gaussian Light

Hermann Haken

Ki-min Park B, Petr Marek, Radim Filip

We propose a conditional implementation of superpositions of Gaussian operations on different modes of light. These operations are conditional entanglers generating non-Gaussian entanglement between two modes of propagating light beams. The all-optical operations emulate weak effects of highly nonlinear operations only available when light interacts with individual atoms. In particular, we propose schemes to implement superposition of coherent displacements and squeezings on two beams of light and discuss physical properties of generated non-Gaussian entanglement. These methods together with high quality of optical tomography of highly nonclassical states allow one to understand non-Gaussian entangling processes.

Tom Kuusela

We describe a simple and compact electrical version of a pseudothermal light source. The source is based on electrical white noise whose spectral properties are tailored by analog filters. This signal is used to drive a light-emitting diode. The type of second-order coherence of the output light can be either Gaussian or Lorentzian, and the intensity distribution can be either Gaussian or non-Gaussian. The output light field is similar in all viewing angles, and thus, there is no need for a small aperture or optical fiber in temporal coherence analysis.

E. Wolf

R.W. Smith

Mariano Uria, Alejandra Maldonado-Trapp, Carla Hermann-Avigliano +1 more

Light-matter interactions that are nonlinear with respect to the photon number reveal the quantum nature of coherent states. We characterize how coherent states depart from Gaussian by the emergence of negative values in their Wigner function during the evolution while maintaining their characteristic Poissonian photon statistics. Such states have nonminimum uncertainty yet present a metrological advantage that can reach the Heisenberg limit. Non-Gaussianity of light arises as a general property of nonlinear interactions, which only requires a polarizable media, resonant or dispersive. Our results highlight how useful quantum features can be extracted from the seemingly most classical states of light, a relevant phenomenon for quantum optics applications.