Nonlinear optical phenomena in fluoride glass and hybrid fibres

Abstract

This thesis investigates nonlinear optical phenomena in non-silica fibres,in a first part utilising a fluoride fibre, followed by the exploration of hybridfibres with an organic single crystal inside a fibre capillary. The uniqueproperties of 55ZrF4, 18BaF2, 6LaF3, 4AlF3, 17NaF (ZBLAN) glass allow thecreation of optical fibres with a highly extended transmission window on thelonger wavelength side. We investigated the properties of ZBLAN fibres inorder to optimise supercontinuum (SC) generation in a ZBLAN fibre pumpedby an optic parametric amplifier. To study applications of the ZBLAN SCwe integrated the SC into a pump-probe setup, being used as a near-infraredbroadband probe source. We have carried out proof-of-principle measurementson an organic copolymer thin-film, showing the possibility of utilising aZBLAN SC, allowing to extend the usability of broadband sources to the nearandmid-infrared, while simplifying the usage of the setup.The second part of this thesis explores the possibilities of hybrid fibres byusing a hollow-core silica capillary with an organic single-crystal inside. Wehave developed and optimised a method to grow an organic semiconductingcrystal inside a hollow core capillary based on the Bridgman-technique. Wecould demonstrate the filling of the inner capillary for diameters down to 1 mand with different materials based on the anthracene structure, opening uppossibilities for various hybrid fibres. The quality of the single-crystals wasevaluated by micro-Raman and X-ray diffraction measurements. We couldaccess nonlinear properties of the crystal by coupling light with an energylower than the band-gap into the fibre. Stimulated by two-photon absorptionphoto-luminescence from the fibre core was observed for the hybrid fibre. Theresults obtained for the hybrid fibres gives rise to a vast amount of possibilitiesfor different hybrid fibres with tailored optical properties of organic materialsand their optimisation in the guiding of light.

Date of Award	25 May 2017
Original language	English
Awarding Institution	University of Bath
Supervisor	Enrico Da Como (Supervisor)