从随机散斑到“浑浊透镜”——基于波前整形的散射光聚焦技术（特邀）

Abstract

Significance Scattering medium is a substance commonly found in nature such as turbid atmosphere, smoke, and biological tissues. Coherent light beams propagating through scattering media will be disrupted due to random scattering effects. The wavefront will be destroyed, and the transmission direction will deviate from the original input direction and becomes chaotic. Random scattered light interference will form a particlelike intensity pattern, known as an optical speckle . In multimode fibers, due to mode dispersion and intermodal interference, a similar scattering distribution will be formed. Thus, multimode fibers are also regarded as a special class of scattering medium .Due to the scattering phenomenon, it is difficult to maintain the original spatial distribution of the light beam , and the energy is exponentially attenuated with the increasing penetration depth, which greatly limits the applications of advanced technologies such as optical tweezers, optical communications, and biomedicine in a strong scattering environment. However, in 1990, Freund proposed that light scattering in static scattering media is a deterministic linear process, a property that reveals the possibility of reutilizing the energy of the scattered light field. Due to the existence of a deterministic response relationship between incident and scattered lights, suitable input conditions can lead to the formation of the desired distribution of the output light field after passing through the scattering medium . In 2007, Vellekoop and