Correlations in optical fluctuations in multiple scattering medium and its applications

本文研究了多重散射介质中光涨落的相关性，并发展了它在光子学中的应用。[1]研究了多重散射介质中时空分辨非线性相关测量中的相干耦合效应。在该测量中，将两束激光束注入到介质上，并且测量非线性光学信号的总强度作为两束激光束之间的相对时间延迟和相对空间分离距离的函数。我们研究了作为频率和两束激光之间的波矢差的函数的相干耦合效应的形状因子。的形状因子示出了一个有趣的功能，这是特性的散斑波动内的多次散射介质，即，形状因子不与传输平均自由程的比例，但它的比例与样品的厚度，即使在反射几何形状。[2]研究了光反应和多重散射介质中持续烧孔的时间发展过程。在这种烧孔中，写入激光束通过光反应过程记录介质内部的体积散斑图案，然后，测量由阅读光束激发的发光强度作为写入光束和阅读光束之间的频率或波矢量差的函数。时间发展反映了介质内部散斑强度起伏的统计特性。最大井深为0.26。孔的形状和宽度的样品的厚度，运输平均自由程和吸收长度的依赖关系进行了测量和实验结果显示良好的协议与以前报道的理论计算的基础上的扩散近似。

We investigated correlations in optical fluctuations in multiple scattering medium and developed its applications in photonics.[1] Coherence coupling effect in a multiple scattering mediumCoherence coupling effect in a space and time resolved nonlinear correlation measurement in a multiple scattering medium was investigated. In this measurement two laser beams are injected onto the medium and the total intensity of nonlinear optical signal is measured as a function of the relative time delay and the relative spatial separation distance, between two laser beams. We examined the form factor of the coherence coupling effect as a function of the frequency and the wave vector differences between two laser beams. The form factor shows an interesting feature which is characteristic to the speckle fluctuations inside the multiple scattering medium, that is, the form factor does not scale with the transport mean free path but it scales with the sample thickness even in the refection geometry.[2] Persistent hole burning in multiple scattering mediaTime development of a persistent hole burning in photo-reactive and multiple scattering media was investigated. In this hole burning, a writing laser beam recodes volume speckle pattern inside the medium through the photo-reactive process, then, the luminescence intensity excited by a reading beam is measured as a function of the frequency or the wave vector difference between the writing and the reading beams. The time development reflects the statistics of the intensity fluctuations in the speckle inside the medium. One of the striking results is that the maximum hole depth is 〜0.26. The dependence of the hole shape and width on the sample thickness, transport mean free path and absorption length were measured and experimental results show good agreement with a previously reported theoretical calculation on the basis of a diffusion approximation.