Real-time resilient focusing through a bending multimode fiber

TL;DR

This paper presents a rapid, real-time system for focusing light through a bending multimode fiber, enabling stable imaging and energy delivery during fiber deformation, with significant improvements over previous methods.

Contribution

The authors develop a system that achieves 37ms focusing speed through a multimode fiber, maintaining focus during bending, which is faster and more resilient than prior approaches.

Findings

Focus spot enhancement by two orders of magnitude

Achieves 37ms focusing speed

Maintains focus during fiber bending

Abstract

We introduce a system capable of focusing light through a multimode fiber in 37ms, one order of magnitude faster than demonstrated in previous reports. As a result, the focus spot can be maintained during significant bending of the fiber, opening numerous opportunities for endoscopic imaging and energy delivery applications. We measure the transmission matrix of the fiber by projecting binary-amplitude computer generated holograms using a digital micromirror device and a field programmable gate array controller. The system shows two orders of magnitude enhancements of the focus spot relative to the background.