Wavefront shaping: A versatile tool to conquer multiple scattering in multidisciplinary fields

Optical techniques offer a wide variety of applications as light-matter interac-tions provide extremely sensitive mechanisms to probe or treat target media. Most of these implementations rely on the usage of ballistic or quasi-ballistic photons to achieve high spatial resolution. However, the inherent scattering na-ture of light in biological tissues or tissue-like scattering media constitutes a critical obstacle that has restricted the penetration depth of non-scattered pho-tons and hence limited the implementation of most optical techniques for wider applications. In addition, the components of an optical system are usu-ally designed and manufactured for a fixed function or performance. Recent advances in wavefront shaping have demonstrated that scattering-or compo-nent-induced phase distortions can be compensated by optimizing the wave -front of the input light pattern through iteration or by conjugating the transmis-sion matrix of the scattering medium. This offers unprecedented opportunities in many applications to achieve controllable optical delivery or detection at depths or dynamically configurable functionalities by using scattering media to substitute conventional optical components. In this article, the recent prog-ress of wavefront shaping in multidisciplinary fields is reviewed, from optical focusing and imaging with scattering media, functionalized devices, modula-tion of mode coupling, and nonlinearity in multimode fiber to multimode fi-ber-based applications. Apart from insights into the underlying principles and recent advances in wavefront shaping implementations, practical limita-tions and roadmap for future development are discussed in depth. Looking back and looking forward, it is believed that wavefront shaping holds a bright future that will open new avenues for noninvasive or minimally invasive optical interactions and arbitrary control inside deep tissues. The high degree of freedom with multiple scattering will also provide unprecedented opportunities to develop novel optical devices based on a single scattering medium (generic or customized) that can outperform traditional optical components.

Automated summary

Optical techniques are limited by the scattering nature of light in biological tissues, but wavefront shaping technology offers a solution by compensating for phase distortions. This allows for controllable optical delivery or detection at depth by using scattering media instead of conventional optical components. Novel optical devices based on multiple scattering can outperform traditional components.