AI 中文总结
该研究提出基于模式功率的消失距离概念，通过半解析模型结合模拟与实验验证，确定动态波前整形的实用范围边界，为评估其实际应用提供简单指南。
AI 中文摘要
波前整形（WFS）是一种强大的现代方法，用于控制光在散射介质中的传播，其应用范围从生物医学成像、密码学到自由空间光通信。虽然WFS在静态或缓慢变化的介质中已取得高度成功，但它在动态和扩展散射环境中的实际相关性仍难以评估。特别是，目前尚无简单标准可识别超出该距离后剩余弹道分量不再与散射背景区分开的传播距离。在此，我们引入消失距离，定义为弹道功率等于单个漫射模式所携带功率的传播长度。与表征散射场角随机化的输运平均自由程不同，消失距离基于模式功率识别弹道通道的丢失。超出该距离后，传输或成像不再能依赖弹道分量，而必须利用散射场。我们提出一个简单的半解析模型，该模型通过蒙特卡罗模拟以及单分散和异质散射介质中的实验得到验证，可用于估计消失距离及相关的最小源功率。在代表性散射环境中，发现该转变通常发生在约30-40个散射平均自由程之后。这些结果为评估动态波前整形的实际相关性提供了简单指南。
英文摘要
Wavefront shaping (WFS) is a powerful modern method to control light propagation through scattering media, with applications ranging from biomedical imaging via cryptography to free-space optical communication. While WFS has been highly successful in static or slowly evolving media, its practical relevance in dynamic and extended scattering environments remains difficult to assess. In particular, no simple criterion currently identifies the propagation distance beyond which the residual ballistic component is no longer distinguishable from the scattered background. Here, we introduce the vanishing distance, defined as the propagation length where the ballistic power equals that carried by a single diffuse mode. Unlike the transport mean free path, which characterizes angular randomization of the scattered field, the vanishing distance identifies the loss of the ballistic channel on a modal-power basis. Beyond this distance, transmission or imaging can no longer rely on the ballistic component and must instead exploit the scattered field. We present a simple semi-analytical model, validated against Monte Carlo simulations and experiments in both monodisperse and heterogeneous scattering media, allowing the vanishing distance and the associated minimum source power to be estimated. Across representative scattering environments, the transition is found to occur typically after about 30-40 scattering mean free paths. These results provide a simple guideline for assessing the practical relevance of dynamic wavefront shaping.
Comments5 pages, 4 figures
