Rachel Lennon
PhD project
Towards Flexible Micro-Endoscopy: Compressive Characterisation and Control of Light Propagation Through Multi-mode Optical Fibres
Supervisors
Multi-mode optical fibres make excellent candidates for future micro-endoscopes: promising high-resolution imaging deep inside the body with minimal disruption to surrounding tissue due to their small (~300um diameter) footprint. However, before this can become a reality there are some significant challenges to overcome, which this project aims to address:
As light propagates through optical fibres, the spatial information is scrambled in a complicated manner, meaning that the wavefront emerging from the near end no longer forms an image of the scene at the far end. This scrambling operation must be characterised and inverted to reconstruct the image, which is a complex and time-consuming process. Current methods to characterize the scrambling through optical fibres require access to both the near and far ends. Unfortunately, the scrambling is dependent upon the precise configuration of the optical fibres – any bending, twisting, or changes in temperature alter how the light is scrambled, thus requiring its re-characterisation before image reconstruction can be achieved. This limits the use of such a system as an endoscope where only the near end of the optical fibre is accessible.
In this project we will aim to solve these challenges using a combination of cutting-edge laser beam shaping technology and new computational techniques based on the field of compressive sensing – reconstructing images from undersampled data. The project will involve laboratory-based experiments using lasers, liquid crystal displays and fast cameras. It will also involve programming these devices to work together, and designing new data analysis algorithms.