Spectral-temporal-spatial customization via modulating multimodal nonlinear pulse propagation

TL;DR

This paper introduces a novel method for controlling multimodal nonlinear pulse propagation in multimode fibers using a programmable fiber shaper, enabling high tunability and broadband high peak power for applications like bioimaging and spectroscopy.

Contribution

It presents the first method to modulate and optimize multimodal nonlinear pulse propagation by leveraging spatial and temporal degrees of freedom with a programmable fiber shaper.

Findings

Achieved broadband high peak power through modulation.

Demonstrated tunable multiphoton microscopy imaging.

Enhanced high-dimensional customization of MMF output.

Abstract

Multimode fibers (MMFs) have recently reemerged as attractive avenues for nonlinear effects due to their high-dimensional spatiotemporal nonlinear dynamics and scalability for high power. High-brightness MMF sources with effective control of the nonlinear processes would offer new possibilities for a wide range of applications from high-power fiber lasers, to bioimaging and chemical sensing, and to novel physics phenomena. Here we present a simple yet effective way of controlling nonlinear effects at high peak power levels: by leveraging not only the spatial but also the temporal degrees of freedom of the multimodal nonlinear pulse propagation in step-index MMFs using a programmable fiber shaper. This method represents the first method that enables modulation and optimization of multimodal nonlinear pulse propagation, achieving high tunability and broadband high peak power. Its potential as a nonlinear imaging source is further demonstrated by applying the MMF source to multiphoton microscopy, where widely tunable two-photon and three-photon imaging is achieved with adaptive optimization. These demonstrations highlight the effectiveness of directly modulating multimodal nonlinear pulse propagation to enhance the high-dimensional customization and optimize the high spectral brightness of MMF output. These advancements provide new possibilities for technology advances in nonlinear optics, bioimaging, spectroscopy, optical computing, and material processing.