Hang Chao, Huang Guoxiang
State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China.
Opt Express. 2010 Feb 1;18(3):2952-66. doi: 10.1364/OE.18.002952.
We consider an active-Raman-gain scheme for realizing giant Kerr nonlinearity and superluminal optical solitons in a four-state atomic system with a gain doublet. We show that this scheme, which is fundamentally different from those based on electromagnetically induced transparency (EIT), is capable of working at room temperature and eliminating nearly all attenuation and distortion.We demonstrate that, due to the appearance of a gain spectrum hole induced by the quantum interference effect induced by a signal field, a significant enhancement of Kerr nonlinearity of probe field can be realized effectively, which can be more than ten times larger than that arrived by the EIT-based scheme with the same energy-level configuration. Based on these important features, we obtain a giant cross-phase modulation effect and hence a stable long-distance propagation of optical solitons, which have superluminal propagating velocity and very low generating power.
我们考虑一种有源拉曼增益方案，用于在具有增益双峰的四态原子系统中实现巨大的克尔非线性和超光速光学孤子。我们表明，该方案与基于电磁诱导透明（EIT）的方案有根本不同，能够在室温下工作并消除几乎所有的衰减和失真。我们证明，由于信号场诱导的量子干涉效应导致增益谱出现孔洞，探测场的克尔非线性可以得到显著增强，比具有相同能级配置的基于EIT的方案所实现的克尔非线性大十多倍。基于这些重要特性，我们获得了巨大的交叉相位调制效应，从而实现了光学孤子的稳定长距离传播，这些孤子具有超光速传播速度和非常低的产生功率。
