Low-loss negative refraction by laser-induced magnetoelectric cross coupling
Low-loss negative refraction by laser-induced magnetoelectric cross coupling
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DOI：
10.1103/physreva.79.063818
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发表时间：
2009-01
影响因子：
2.9
通讯作者：
J. Kastel;M. Fleischhauer;S. Yelin;R. Walsworth
中科院分区：
文献类型：
--
作者：
J. Kastel;M. Fleischhauer;S. Yelin;R. Walsworth
讨论了相干驱动原子介质中吸收减少的负折射的可行性。相干耦合的电和磁偶极跃迁的激光场诱导磁电交叉耦合和负折射的偶极密度是远远小于必要的实现负磁导率。同时，由于相消量子干涉，吸收被最小化，并且负折射率与吸收的比率变得比没有相干交叉耦合的系统大几个数量级。所提出的方案允许折射率的微调。我们推导出一个广义表达式的磁电交叉耦合介质的阻抗，并表明阻抗匹配真空可以很容易地实现。最后，我们讨论了介质响应的张量性质，并推导出折射率对传播方向的依赖关系的表达式。
We discuss the feasibility of negative refraction with reduced absorption in coherently driven atomic media. Coherent coupling of an electric and a magnetic dipole transition by laser fields induces magnetoelectric cross coupling and negative refraction at dipole densities which are considerably smaller than necessary to achieve a negative permeability. At the same time the absorption gets minimized due to destructive quantum interference and the ratio of negative refraction index to absorption becomes orders of magnitude larger than in systems without coherent cross coupling. The proposed scheme allows for a fine tuning of the refractive index. We derive a generalized expression for the impedance of a medium with magnetoelectric cross coupling and show that impedance matching to vacuum can easily be achieved. Finally we discuss the tensorial properties of the medium response and derive expressions for the dependence of the refractive index on the propagation direction.