title: Optical precursor with four-wave mixing and storage based on a cold-atom ensemble.
abstract: We observed optical precursors in four-wave mixing based on a cold-atom gas. Optical precursors appear at the edges of pulses of the generated optical field, and propagate through the atomic medium without absorption. Theoretical analysis suggests that these precursors correspond to high-frequency components of the signal pulse, which means the atoms cannot respond quickly to rapid changes in the electromagnetic field. In contrast, the low-frequency signal components are absorbed by the atoms during transmission. We also showed experimentally that the backward precursor can be stored using a Raman transition of the atomic ensemble and retrieved later.
authors: Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.|Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors: Dong-Sheng
authors: DS
authors: Ding
authors: College of Physics and Information Engineering, Fuzhou University, Fuzhou 350002, People's Repubic of China.
authors: Yun Kun
authors: YK
authors: Jiang
authors: Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.|Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors: Wei
authors: W
authors: Zhang
authors: Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.|Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors: Zhi-Yuan
authors: ZY
authors: Zhou
authors: Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.|Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors: Bao-Sen
authors: BS
authors: Shi
authors: Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.|Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors: Guang-Can
authors: GC
authors: Guo