Nearly Perfect Raman Self-Cleaning in Graded-Index Multimode Fibers Using Pearcey-Gaussian Pulses

Abstract Beam self-cleaning (BSC) in graded-index (GRIN) multimode fibers (MMFs) has been recently reported by different research groups. Driven by the interplay between Kerr effect and beam self-imaging, BSC counteracts random mode coupling, and forces laser beams to recover a quasi-single mode profile at the output of GRIN fibers. Here we show that the associated self-induced spatiotemporal reshaping allows for improving the performances of nonlinear fluorescence (NF) microscopy and endoscopy using multimode optical fibers. We experimentally demonstrate that the beam brightness increase, induced by self-cleaning, enables two and three-photon imaging of biological samples with high spatial resolution. Temporal pulse shortening accompanying spatial beam clean-up enhances the output peak power, hence the efficiency of nonlinear imaging. We also show that spatiotemporal supercontinuum (SC) generation is well-suited for large-band NF imaging in visible and infrared domains. We substantiated our findings by multiphoton fluorescence imaging in both microscopy and endoscopy configurations.

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Kerr beam self-cleaning on the LP11 mode in graded-index multimode fibers

OSA Continuum ◽

10.1364/osac.2.001089 ◽

2019 ◽

Vol 2 (4) ◽

pp. 1089 ◽

Cited By ~ 11

Author(s):

E. Deliancourt ◽

M. Fabert ◽

A. Tonello ◽

K. Krupa ◽

A. Desfarges-Berthelemot ◽

...

Keyword(s):

Multimode Fibers ◽

Graded Index ◽

Self Cleaning

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Spatiotemporal Evolutions of Similariton Pulses in Multimode Fibers with Raman Amplification

Photonics ◽

10.3390/photonics8090354 ◽

2021 ◽

Vol 8 (9) ◽

pp. 354

Author(s):

Leila Graini ◽

Bülend Ortaç

Keyword(s):

Peak Power ◽

High Energy ◽

Cleaning Process ◽

Raman Amplification ◽

Spectral Evolution ◽

Picosecond Pulses ◽

Multimode Fibers ◽

Graded Index ◽

Spatial Beam ◽

Self Cleaning

This paper aims to pave the way towards the demonstration of spatiotemporal similariton pulses’ evolution in passive multimode fibers with Raman amplification. We numerically present this issue in graded-index and step-index multimode fibers and provide a first look at the complex spatiotemporal dynamics of similariton pulses. The results showed that the similariton pulses could be generated in both multimode fibers. The temporal and spectral evolution of the pulses can be characterized as parabolic shapes with linear chirp and kW peak power. By compressing these, high-energy femtoseconds pulses can be obtained, starting initial picosecond pulses. A spatial beam profile could be preserved in both multimode fibers with the most energy coupled to the fundamental mode. Specifically, the similariton pulses’ generation with Raman amplification in a graded-index multimode fiber improves the spatial beam self-cleaning process under the different initial modes’ excitation. The observation of a new beam self-cleaning process is another attractor feature of propagation in graded-index multimode fibers.

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Spatiotemporal beam self-cleaning for high-resolution nonlinear fluorescence imaging with multimode fiber

Scientific Reports ◽

10.1038/s41598-021-96753-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nawell Ould Moussa ◽

Tigran Mansuryan ◽

Charles-Henri Hage ◽

Marc Fabert ◽

Katarzyna Krupa ◽

...

Keyword(s):

Fluorescence Imaging ◽

Optical Fibers ◽

Kerr Effect ◽

Single Mode ◽

Multimode Fibers ◽

Graded Index ◽

Output Peak Power ◽

Spatial Beam ◽

Self Cleaning ◽

Nonlinear Imaging

AbstractBeam self-cleaning (BSC) in graded-index (GRIN) multimode fibers (MMFs) has been recently reported by different research groups. Driven by the interplay between Kerr effect and beam self-imaging, BSC counteracts random mode coupling, and forces laser beams to recover a quasi-single mode profile at the output of GRIN fibers. Here we show that the associated self-induced spatiotemporal reshaping allows for improving the performances of nonlinear fluorescence (NF) microscopy and endoscopy using multimode optical fibers. We experimentally demonstrate that the beam brightness increase, induced by self-cleaning, enables two and three-photon imaging of biological samples with high spatial resolution. Temporal pulse shortening accompanying spatial beam clean-up enhances the output peak power, hence the efficiency of nonlinear imaging. We also show that spatiotemporal supercontinuum (SC) generation is well-suited for large-band NF imaging in visible and infrared domains. We substantiated our findings by multiphoton fluorescence imaging in both microscopy and endoscopy configurations.

Download Full-text