论文标题
高斯光束引起的两个对称四波混合信号的空间分布
Spatial distribution of two symmetric four-wave mixing signals induced by Gaussian beams
论文作者
论文摘要
我们对在两级原子的薄样品中诱导的两个简并四波混合的对称信号的空间形状进行了理论分析。我们的计算考虑了控制这两个过程的相关非线性敏感性的全部空间和光谱依赖性。这揭示了两个有趣的效果。第一个是，入射梁的总功率会影响介质出口处的四波混合信号的横向轮廓及其自由传播。第二个是培养基在自由传播时两个产生信号的纵向谱的光谱特征的影响。我们认为，第一种效应可以看作是较高强度区域中培养基的饱和度，而第二个效果可以理解为原子介质内折射率的非线性贡献的结果。这些效果可以在两个信号之间对称，而因入射场的共振而引起的不对称性引起了不对称。
We present a theoretical analysis of the spatial shape of two symmetric signals of degenerate four-wave mixing induced by Gaussian beams in a thin sample of two-level atoms. Our calculations take into account the full spatial and spectral dependencies of the relevant nonlinear susceptibilities that govern the two processes. This reveals two interesting effects. The first one is that the total power of incident beams affects the transverse profile of the four-wave mixing signals at the medium exit and their free propagation. The second one is the influence of the spectral characteristics of the medium on the longitudinal profile of both generated signals upon free propagation. We argue that the first effect can be seen as the saturation of the medium in regions of higher intensity, while the second can be understood as the result of a nonlinear contribution to the refractive index inside the atomic medium. These effects can be symmetric between the two signals, with asymmetries induced by different detunings from resonance of the incident fields.
