Zhang Bin, Zhang Zhenfeng, Feng Qi, Lin Chengyou, Ding Yingchun
Department of Physics, Beijing University of Chemical Technology, Beijing, 100029, China.
Sci Rep. 2018 Apr 23;8(1):6385. doi: 10.1038/s41598-018-24698-0.
This paper investigates the reference-defining-criterion problem in the field of light focusing through scattering media. In many analogous light focusing experiments, the enhancement values differ greatly from each other. By analyzing the focusing picture after optimizations, we concluded that the discrepancy in enhancement originates from the unclear definition of reference boundary. By averaging multiple speckle backgrounds, we found that the intensity of speckle background obeys circular Gaussian distribution. Based on the intensity statistics and Gaussian-function fitting to the speckle background, we proposed a clear reference-defining criterion- 1/e criterion. With this reference-defining criterion, we have carried out light focusing experiments with the speckle backgrounds possessing different shape and size. The enhancements obtained from the repetitive experiments for both weakly scattering medium and strongly scattering medium were all in the reasonable range, demonstrating its validity and universality. This criterion will provide a comparison standard for light focusing experiments in wavefront-shaping field.
本文研究了通过散射介质进行光聚焦领域中参考定义标准的问题。在许多类似的光聚焦实验中，增强值彼此差异很大。通过分析优化后的聚焦图像，我们得出增强差异源于参考边界定义不明确的结论。通过对多个散斑背景进行平均，我们发现散斑背景的强度服从圆形高斯分布。基于强度统计和对散斑背景的高斯函数拟合，我们提出了一个明确的参考定义标准——1/e标准。利用这个参考定义标准，我们对具有不同形状和尺寸的散斑背景进行了光聚焦实验。对弱散射介质和强散射介质进行重复实验所获得的增强值均在合理范围内，证明了其有效性和通用性。该标准将为波前整形领域的光聚焦实验提供一个比较标准。
