Speckle patterns produced by disordered scattering systems exhibit a sensitivity to addition of individual particles, which can be used for sensing applications. Using a coupled dipole model we investigate how multiple scattering can enhance field perturbations arising in such random-scattering-based sensors. Three distinct families of multiple scattering paths are shown to contribute and the corresponding complex enhancement factors derived. Probability distributions of individual enhancement factors over the complex plane are characterised numerically within the context of surface plasmon polariton scattering in which absorption is shown to play an important role. We show that enhancements become more strongly dependent on individual scatterer properties when absorption losses are larger, however, amplitude enhancements $\sim {10}^2$, comparable to low-loss surface plasmons, are achievable through sensor optimisation. Approximate analytic expressions for the complex mean enhancements are also found, which agree well with simulations when loop contributions are negligible.

中文翻译：

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多次散射在吸收随机介质中单粒子扰动中的作用

由无序散射系统产生的散斑图案对添加单个粒子表现出敏感性，可用于传感应用。我们使用耦合偶极子模型研究多重散射如何增强这种基于随机散射的传感器中出现的场扰动。显示出三个不同的多散射路径族有所贡献，并导出了相应的复杂增强因子。复平面上单个增强因子的概率分布在表面等离子体极化子散射的背景下进行了数值表征，其中吸收显示起重要作用。我们表明，当吸收损耗较大时，增强变得更加依赖于单个散射体的特性，然而，振幅增强$～{10}^2$，可与低损耗表面等离子体激元相媲美，可通过传感器优化实现。还发现了复杂平均增强的近似解析表达式，当循环贡献可忽略不计时，它们与模拟非常吻合。