Strong Entanglement of Bright Light Beams in Controlled Quantum Systems

Abstract

We investigate some aspects of continuous-variable (CV) entanglement of lightields in controlled quantum dissipative systems. We discuss entangling resources of a nondegenerate optical parametric oscillator (NOPO) in transition through the generation threshold as well as in the regime of lasing. We review our proposal for the creation of CV entanglement in the presence of phase-localizing processes and discuss properties of entangled light-fields with well-defined distinct phases in application to quantum communications. We propose a new approach for the generation of strongly entangled Einstein-Podolsky-Rosen states of intense light beams based on the time-modulation of quantum dissipative dynamics. We demonstrate an essential improvement of the degree of entanglement in time-modulated NOPO in comparison with the ordinary one, if the frequency of modulation is close to the decay rate of the dissipative processes.