It is known that spontaneous Raman scattering is accompanied by the appearance of nonclassical cross correlations of photons at Stokes and anti-Stokes frequencies. Such correlations occur due to the internal nonlinear interaction between electronic and nuclear vibration degrees of freedom. Since the properties of a given media are unchangeable, the possibilities for controlling the cross correlations are limited. This, in turn, restricts the possible applications of the correlated light obtained during the spontaneous Raman scattering. In this work, we investigate the influence of statistical properties of an incident light on the cross correlations of Stokes and anti-Stokes light. We show that the incoherence of the incident light results not only in the incoherence of the scattered light but also in the enhancement of the interbeam coherence at different frequencies. We demonstrate that the cross correlations of Stokes and anti-Stokes light intensities are enhanced when the incident light with high second-order autocorrelation function is applied. Our results pave the way to control correlated light obtained in the process of spontaneous Raman scattering.

中文翻译：

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经典非相干入射光增强了斯托克斯-反斯托克斯相关性

已知自发的拉曼散射伴随着在斯托克斯频率和反斯托克斯频率的光子的非经典互相关的出现。由于电子和核振动自由度之间存在内部非线性相互作用，因此会发生这种相关性。由于给定媒体的属性不可更改，因此控制互相关的可能性受到限制。反过来，这限制了在自发拉曼散射期间获得的相关光的可能应用。在这项工作中，我们研究了入射光的统计特性对斯托克斯光和反斯托克斯光的互相关的影响。我们表明，入射光的不相干性不仅导致散射光的不相干性，而且还导致不同频率下光束间相干性的增强。我们证明当应用具有高二阶自相关函数的入射光时，斯托克斯和反斯托克斯光强度的互相关得到增强。我们的结果为控制自发拉曼散射过程中获得的相关光铺平了道路。