Host Laboratory / Laboratoire d’Accueil
Institut FEMTO-ST – CNRS – Optics Department
University Bourgogne Franche-Comté – Besançon, France
Keywords
Optics, Photonics, Nonlinear Optics, Fiber Optics, Laser, Supercontinuum physics
Job description
The physics and applications of fiber-based supercontinuum (SC) broadband light sources have been a subject of much interest over the last decade, with significant impact on both basic science and industry. New uses are constantly emerging due to their unique properties that combine high brightness, multi-octave bandwidth, fiber delivery, and single-mode output. The last few years have also seen significant research efforts focused on extending the wavelength coverage of SC sources towards the 2 to 20 μm molecular fingerprint mid-infrared (MIR) region and in the ultraviolet (UV) down to 100 nm, while also improving stability, noise and coherence properties.
This thesis project is twofold. First it aims to investigate, both numerically and experimentally, the physics of SC generation in novel photonic gas cells using the evanescent field of sub-wavelength silica fiber tapers, as an alternative method to gas-filled hollow-core fibers. We expect novel evanescently-induced nonlinear effects in nanophotonic gas cells with strong potential for SC applications towards both the UV range and the mid-IR ranges.
Another topic covered by this thesis will be to explore SC generation in all-normal dispersion (ANDi) fibers that provide ultra-flat, low-noise, and coherent SC spectra, from self-phase modulation (SPM) and optical wave breaking (OWB). The latter effect (OWB) has not been fully investigated and exploited for SC generation. This thesis aims to investigate, both numerically and experimentally, the effect of OWB in ANDi fibers and to provide an unified analysis with the four-wave mixing (FWM) theory and phase-matching conditions, and the dispersive shock wave formation in the time domain. The experiment will be based on a full-time/frequency analysis of femtosecond pulses propagating in parabolic dispersion fibers, both of which are already available in the lab. Ultimately, the main objective will be to improve the bandwidth and noise properties of SC sources based on parabolic dispersion fibers.
More information
Contact
Thibaut Sylvestre
Directeur de Recherche CNRS
Institut FEMTO-ST
Département d’Optique P. M. Duffieux
Université Bourgogne Franche-Comté
CNRS UMR 6174
15 Avenue des Montboucons
25030 Besançon Cedex
Tel: +33676353156
