When light propagates through a complex medium, such as a multimode optical fiber (MMF), the spatial information it carries is scrambled. In this work we experimentally demonstrate an all-optical strategy to unscramble this light again. We first create a digital model capturing the way light has been scattered, and then use this model to inverse-design and build a complementary optical system–which we call an optical inverter–that reverses this scattering process. Our implementation of this concept is based on multi-plane light conversion, and can also be understood as a physical matrix pre-conditioner, or a linear diffractive optical neural network. We present three design strategies allowing different aspects of device performance to be prioritized. We experimentally demonstrate a prototype optical inverter capable of simultaneously unscrambling up to 30 spatial modes that have propagated through a 1 m long MMF, and show how this promises near instantaneous incoherent imaging, without the need for any beam scanning or computational processing. We also demonstrate the reconfigurable nature of this prototype, allowing it to adapt and deliver a new optical transformation if the MMF it is matched to changes configuration. Our work represents a step towards a new way to see through scattering media. Beyond imaging, this concept may also have applications to the fields of optical communications, optical computing and quantum photonics.

中文翻译：

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全光学解开多模光纤中的光传播

当光通过多模光纤 (MMF) 等复杂介质传播时，其携带的空间信息会被扰乱。在这项工作中，我们通过实验演示了一种全光学策略来再次解读这种光。我们首先创建一个捕获光散射方式的数字模型，然后使用该模型进行逆向设计并构建一个互补的光学系统（我们称之为光学逆变器），以逆转这种散射过程。我们对这个概念的实现是基于多平面光转换，也可以理解为物理矩阵预处理器，或者线性衍射光学神经网络。我们提出了三种设计策略，可以优先考虑设备性能的不同方面。我们通过实验演示了一种原型光学逆变器，能够同时解扰通过 1 m 长的 MMF 传播的多达 30 个空间模式，并展示了这如何保证近乎瞬时的非相干成像，而无需任何光束扫描或计算处理。我们还展示了该原型的可重新配置性质，如果其匹配的 MMF 改变配置，它就可以适应并提供新的光学转换。我们的工作代表着向一种透视散射介质的新方法迈出了一步。除了成像之外，这个概念还可能应用于光通信、光计算和量子光子学领域。