We experimentally and numerically study the ignition of helical-shaped plasma filaments in standard optical fibers. Femtosecond pulses with megawatt peak power with proper off-axis and tilted coupling in the fiber core produce plasma skew rays. These last for distances as Read More …
Autore: laboratorio
Femtosecond nonlinear losses in multimode optical fibers
Multimode optical fibers are attracting a growing interest for their capability to transport high-power laser beams, coupled with novel nonlinear optics-based applications. However, optical fiber breakdown occurs when beam intensities exceed a certain critical value. Optical breakdown associated with irreversible Read More …
Multimode solitons in step-index fibers
We experimentally generate multimode solitons in step-index fibers, where nonlinearity compensates for both chromatic and modal dispersion. These solitons are subject to Raman self-frequency shift, and their energy is gradually transfered to the fundamental fiber mode. We compare multimode soliton Read More …
NOSTER
Spatiotemporal beam self‑cleaning for high‑resolution nonlinear fuorescence imaging with multimode fber
Beam self-cleaning (BSC) in graded-index (GRIN) multimode fbers (MMFs) has been recently reported by diferent research groups. Driven by the interplay between Kerr efect and beam self-imaging, BSC counteracts random mode coupling, and forces laser beams to recover a quasi-single Read More …
Conditions for walk-off soliton generation in a multimode fiber
It has been recently demonstrated that multimode solitons are unstable objects which evolve, in the range of hundreds of nonlinearity lengths, into stable single-mode solitons carried by the fundamental mode. We show experimentally and by numerical simulations that femtosecond multimode Read More …
Experimental observation of self-imaging in SMF-28 optical fibers
Spatial self-imaging, consisting of the periodic replication of the optical transverse beam profile along the propagation direction, can be achieved in guided wave systems when all excited modes interfere in phase. We exploited material defects photoluminescence for directly visualizing self-imaging Read More …
3D time-domain beam mapping for studying nonlinear dynamics in multimode optical fibers
Characterization of the complex spatiotemporal dynamics of optical beam propagation in nonlinear multimode fibers requires the development of advanced measurement methods, capable of capturing the real-time evolution of beam images. We present a new space–time mapping technique, permitting the direct Read More …