Continuous spatial self-cleaning in GRIN multimode fiber for self-referenced multiplex CARS imaging
Sahar Wehbi, Tigran Mansuryan, Katarzyna Krupa, Marc Fabert, Alessandro Tonello, Mario Zitelli, Mario Ferraro, Fabio Mangini, Yifan Sun, Sébastien Vergnole, Hideaki Kano, S. Wabnitz, Vincent Couderc
Abstract
We demonstrate how spatial beam self-cleaning and supercontinuum generation in graded-index multimode optical fibers can be directly applied in multiplex coherent anti-Stokes Raman Scattering (M-CARS) spectroscopy. Although supercontinuum generation causes pump depletion mainly in the center of the beam, the partial recovery of the pump brightness due to self-cleaning may enable self-referenced M-CARS, with no additional delay lines to synchronize pump and Stokes waves. As a proof-of-principle, we report examples of imaging of single chemical compounds and polystyrene beads. The new scheme paves the way towards simpler M-CARS systems based on multimode fiber sources.