Abstract
Motivated by recent experiments, we study four-wave-mixing in an atomic double- system driven by a far-detuned pump. Using the Heisenberg-Langevin formalism, and based on the microscopic properties of the medium, we calculate the classical and quantum properties of seed and conjugate beams beyond the linear amplifier approximation. A continuous-variable approach gives us access to relative-intensity noise spectra that can be directly compared with experiments. Restricting ourselves to the cold-atom regime, we predict the generation of quantum-correlated beams with a relative-intensity noise spectrum well below the standard quantum limit (down to dB). Moreover, entanglement between seed and conjugate beams measured by an inseparability down to is expected. This work opens the way to the generation of entangled beams by four-wave mixing in a cold-atom sample.
- Received 9 July 2010
DOI:https://doi.org/10.1103/PhysRevA.82.033819
©2010 American Physical Society