We propose to transfer quantum correlations from atoms to light by Raman scattering of a strong laser pulse on a spin-squeezed atomic sample. We prove that the emission is restricted to a single field mode which perfectly inherits the quantum correlations of the atomic system.
A proof is given using, a quantized single mode field in interaction with an atom in non-relativistic approximation, that the scattered light in strong laser–atom interaction can be made coherent to squeezed by properly choosing the wavelength of the laser, the density of the sample of atoms at the laser beam and the pulse duration. In the experiments with gases for harmonic generation, at the current laser wavelengths this effect is too small to be observed and the term of the square of the field in the Hamiltonian can be safely neglected. Then, the observed light is purely coherent.
A proof is given using, a quantized single mode field in interaction with an atom in non-relativistic approximation, that the scattered light in strong laser–atom interaction can be made coherent to squeezed by properly choosing the wavelength of the laser, the density of the sample of atoms at the laser beam and the pulse duration. In the experiments with gases for harmonic generation, at the current laser wavelengths this effect is too small to be observed and the term of the square of the field in the Hamiltonian can be safely neglected. Then, the observed light is purely coherent.
We theoretically propose a method to enhance Raman scattering by injecting a seeded light field which is correlated with the initially prepared atomic spin wave. Such a light-atom correlation leads to an interference in the Raman scattering. The interference is sensitive to the relative phase between the seeded light field and initially prepared atomic spin wave. For constructive interference, the Raman scattering is greatly enhanced. Such an enhanced Raman scattering may find applications in quantum information, nonlinear optics, and optical metrology due to its simplicity.
Enhanced Raman scattering can be obtained by the initially prepared atomic spin excitation, or by injecting a seeded light field which is correlated with the initially prepared atomic spin excitation. This paper theoretically calculated the quantum fluctuations of the quadrature components of the two-mode photon-atom quantum interface and found that the enhanced Raman scattering based on coherence can improve the initial photon-atom squeezing slightly in a certain scope, and correlation-enhanced Raman scattering can produce strong two-mode squeezing of photon-atom. Such a strong two-mode squeezed state at the photon-atom interface has very important applications in precision measurement research based on the light field and atomic system.