论文标题
空间kramers-kronig关系和冷原子中的单向反射
Spatial Kramers-Kronig relation and controlled unidirectional reflection in cold atoms
论文作者
论文摘要
我们提出了一个模型，用于实现冷原子样品中探针敏感性的频率空间变化。发现发现频域中探头易感性的真实部分和假想部分之间的通常的kramers-kronig（kk）可以将其映射到空间域中，因为使用了空间线性线性变化的远谐振的控制场。这种非热培养基显示出从左或右样品端入射的探针光子的单向反射频带。我们可以通过分别更改控制场强度和频率来调整频带并选择对应于消失的反射率的方向是特别感兴趣的。对于逼真的原子密度而言，从另一个方向的非零反射率通常很小，但是可以通过将bragg散射纳入空间KK关系，从而在很大程度上得到增强，从而实现高反射率对比度。
We propose a model for realizing frequency-dependent spatial variations of the probe susceptibility in a cold atomic sample. It is found that the usual Kramers-Kronig (KK) relation between real and imaginary parts of the probe susceptibility in the frequency domain can be mapped into the space domain as a far detuned control field of intensity linearly varied in space is used. This non-Hermitian medium exhibits then a unidirectional reflectionless frequency band for probe photons incident from either the left or the right sample end. It is of special interest that we can tune the frequency band as well as choose the direction corresponding to the vanishing reflectivity by changing, respectively, the control field intensity and frequency. The nonzero reflectivity from the other direction is typically small for realistic atomic densities, but can be largely enhanced by incorporating the Bragg scattering into the spatial KK relation so as to achieve a high reflectivity contrast.
