TY - GEN

T1 - Spatiotemporal guided bullets in multimode fiber

AU - Zitelli, M.

AU - Ferraro, M.

AU - Mangini, F.

AU - Leggio, L.

AU - Kharenko, D. S.

AU - Niang, A.

AU - Tonello, A.

AU - Couderc, V.

AU - Hansson, T.

AU - Wabnitz, S.

N1 - Funding Information: We acknowledge the financial support from the European Union's Horizon 2020 Research and Innovation Programme via the European Research Council (Grants No. 874596 and No. 740355), the Italian Ministry of University and Research (Grant No. R18SPB8227), and the Russian Ministry of Science and Education (Grant No. 14.Y26.31.0017) Funding Information: We acknowledge the financial support from the European Union’s Horizon 2020 Research and Innovation Programme via the European Research Council (Grants No. 874596 and No. 740355), the Italian Ministry of University and Research (Grant No. R18SPB8227), and the Russian Ministry of Science and Education (Grant No. 14.Y26.31.0017) Publisher Copyright: © 2021 SPIE.

PY - 2021

Y1 - 2021

N2 - Beam self-imaging of ultrashort pulses in nonlinear graded-index (GRIN) multimode optical fibers is of interest for many applications, including spatiotemporal mode-locking in fiber lasers. We obtained a new analytical description for the nonlinear evolution of a laser beam of arbitrary transverse shape propagating in a GRIN fiber. The longitudinal beam evolution could be directly visualized by means of femtosecond laser pulses, propagating in the anomalous or in the normal dispersion regime, leading to light scattering out of the fiber core via the emission of blue photo-luminescence. As the critical power for self-focusing is approached and even surpassed, a host of previously undisclosed nonlinear effects is revealed, including strong multiphoton absorption by oxygen-deficiency center defects and Germanium inclusions, splitting and shifting of the self-imaging period, filamentation, and conical emission of the guided light bullets. We discovered that nonlinear loss has a profound influence on the process of high-order spatiotemporal soliton fission. The beam energy carried by the fiber is clamped to a fixed value, and nonlinear bullet attractors with suppressed Raman frequency shift and fixed temporal duration are generated, leading to highly efficient frequency conversion of the input near-infrared femtosecond pulses into mid-infrared multimode solitons.

AB - Beam self-imaging of ultrashort pulses in nonlinear graded-index (GRIN) multimode optical fibers is of interest for many applications, including spatiotemporal mode-locking in fiber lasers. We obtained a new analytical description for the nonlinear evolution of a laser beam of arbitrary transverse shape propagating in a GRIN fiber. The longitudinal beam evolution could be directly visualized by means of femtosecond laser pulses, propagating in the anomalous or in the normal dispersion regime, leading to light scattering out of the fiber core via the emission of blue photo-luminescence. As the critical power for self-focusing is approached and even surpassed, a host of previously undisclosed nonlinear effects is revealed, including strong multiphoton absorption by oxygen-deficiency center defects and Germanium inclusions, splitting and shifting of the self-imaging period, filamentation, and conical emission of the guided light bullets. We discovered that nonlinear loss has a profound influence on the process of high-order spatiotemporal soliton fission. The beam energy carried by the fiber is clamped to a fixed value, and nonlinear bullet attractors with suppressed Raman frequency shift and fixed temporal duration are generated, leading to highly efficient frequency conversion of the input near-infrared femtosecond pulses into mid-infrared multimode solitons.

KW - Light bullets

KW - Multimode fiber

KW - Optical solitons

KW - Raman scattering

KW - Self-focusing

KW - Ultrashort pulses

UR - http://www.scopus.com/inward/record.url?scp=85107031574&partnerID=8YFLogxK

U2 - 10.1117/12.2578222

DO - 10.1117/12.2578222

M3 - Conference contribution

AN - SCOPUS:85107031574

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Nonlinear Frequency Generation and Conversion

A2 - Schunemann, Peter G.

A2 - Schepler, Kenneth L.

PB - SPIE

T2 - Nonlinear Frequency Generation and Conversion: Materials and Devices XX 2021

Y2 - 6 March 2021 through 11 March 2021

ER -