Qiao Yanqi, Peng Yajun, Zheng Yuanlin, Ye Fangwei, Chen Xianfeng
Opt Lett. 2017 May 15;42(10):1895-1898. doi: 10.1364/OL.42.001895.
Scattering has usually been considered detrimental for optical focusing or imaging. Recently, more and more research has shown that strongly scattering materials can be utilized to focus coherent light by controlling or shaping the incident light. Here, purposeful focusing of second-harmonic waves, which are generated and scattered from nonlinear turbid media via feedback-based wavefront shaping, is presented. This Letter shows a flexible manipulation of both disordered linear and nonlinear scattering signals, indicating more controllable degrees of freedom for the description of turbid media. This technique also provides a possible way to an efficient transmission of nonlinear signal at a desired location in the form of a focal point or other patterns. With the combination of random nonlinear optics and wavefront shaping methods, more interesting applications can be expected in the future, such as nonlinear transmission matrix, multi-frequency imaging, and phase-matching-free nonlinear optics.
散射通常被认为对光学聚焦或成像有害。最近，越来越多的研究表明，通过控制或塑造入射光，可以利用强散射材料来聚焦相干光。在此，展示了通过基于反馈的波前整形从非线性混浊介质中产生并散射的二次谐波的有目的聚焦。这封信展示了对无序线性和非线性散射信号的灵活操控，表明在描述混浊介质时有更多可控自由度。该技术还提供了一种可能的方式，以焦点或其他图案的形式在期望位置高效传输非线性信号。随着随机非线性光学和波前整形方法的结合，未来有望出现更有趣的应用，如非线性传输矩阵、多频成像和无相位匹配非线性光学。
