Development of Ultraviolet Optical Fibres

My project is based on development of ultraviolet optical fibres. Specifically, to make a fibre which can guide light at wavelengths below 190 nm. The challenge lies in the fact that silica glass (the most commonly used material fibres are made from) absorbs light at these energies. Thus, one would need to make a fibre with a hollow-core so no material loss occurs. There are many different types of hollow-core fibres, but the most likely candidate for this task is known as a negative-curvature fibre. They are characterized by the negative curvature of the core wall which reduces the attenuation. Furthermore, one can design these fibres so the cladding or resonators are not touching, known as free boundary, which reduces the likelihood of core modes coupling with cladding modes which would further reduce the loss. The challenge in this project is the manufacturing of the fibre. At these short wavelengths the sensitivity of transmission bands is very high with respect to the thickness of the cladding walls. Ensuring the fibre is homogeneous along its length will be difficult. Moreover, to test the fibre a sub 190 nm light source will be needed along with a detector which senses at these wavelengths. So as well as modelling, designing and fabricating the fibre, a testing and characterisation set-up will need to be created and employed. Although, I will be working with collaborators who do have the means to test the fibre making the end goal more attainable.

This is an untapped part of fibre optics which has the potential to open up new barriers of research. Likely applications are in the fields of astrophotonics and medicine, however, as an unexplored area the uses of this type of fibre may be much more broad.