Deterministic versus spontaneous process in atomic four wave mixing

Heurich, Jan-Erik, Heurich, Jan-Erik

Guo Guang-Can

Generation of non-classical correlated photon pairs via spontaneous four-wave-mixing(FWM) in cold atomic ensembles is a promising field in quantum information process.In this paper we report on the realization of stimulated four-wave-mixing based on the cold 85Rb atoms,which is prepared in a magnetic-optical trap.We have observed the spatial distribution of the output parametric field,and briefly discussed how the intensities and frequencies of the three input beams affect this process.Temporal sequences modulation is used to control the interaction for the subsequent work of generating the non-classical correlated photon pairs.

Yin Cai, Ling Yun Hao, Da Zhang +5 more

Multimode entanglement is essential for the generation of quantum networks, which plays a central role in quantum information processing and quantum metrology. Here, we study the spatial multimode entanglement characteristics of the large scale quantum states via a dual-pumped four-wave-mixing (FWM) process of Rubidium atomics vapors. A linear mode transform approach is applied to solve the four- and six-mode Gaussian states and the analytical input-output relations are presented. Moreover, via reconstructing the full covariance matrix of the produced states, versatile entanglement with from two up to six modes is analyzed. The results show that most of the 1 versus n-mode and m versus n-mode states are entangled, and the amount of entanglement can be regulated due to the competitions of mode components caused by different interaction strengths of co-existing FWMs. Our study could be applied for any multimode Gaussian states with a quadratic Hamiltonian.

Daniel Pertot, Bryce Gadway, Dominik Schneble

Karsten K. Rottwitt

Taek Jeong, Young-Tak Chough, Han Seb Moon

We report on the dynamic manipulation of light in a warm 87Rb atomic ensemble using light storage based on the atomic spin coherence arising from the electromagnetically induced transparency (EIT) and spontaneous four-wave mixing (FWM) processes. We demonstrate that, subsequent to the generation of atomic spin coherence between two hyperfine ground states via the EIT storage process, it is possible to control the delay time, direction, and optical frequency of the retrieved light according to the timing sequence and powers of the coupling, probe, and driving lasers used for atomic-spin-coherence generation and the spontaneous FWM process. We believe that our results provide useful ideas in photon frequency conversion and photon control in connection with the quantum memories that is essential in the quantum communications technology.