Keenlyside, Benjamin;
(2024)
Interrogation of Fabry Perot ultrasound sensors through multimode fibre for photoacoustic tomography.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Photoacoustic Tomography (PAT) is a powerful biomedical imaging modality that allows visualising specific absorbing structures in tissue up to depths of several centimetres. Fabry Perot Ultrasound Sensor (FPUS)s are particularly attractive as sensors for PAT, combining small detection element size, high sensitivity, broad bandwidth and the ability to straightforwardly fabricate arrays containing thousands of effective detection elements. FPUSs are usually read out by scanning a focused beam across the sensor using rotating mirrors and monitoring the reflected power. In this thesis I present an alternative readout concept, in which an FPUS is interrogated through a Multimode Fibre (MMF). This requires the use ofWavefront Shaping (WFS) in order to compensate for modal dispersion in MMF, which otherwise scrambles the beam transmitted through it producing a pseudo-random speckle pattern. The approach promises a number of advantages over existing systems, including miniaturisability, dynamic beam structuring, and Magnetic Resonance Imaging (MRI) compatibility. A prototype imaging system based on interrogating an FPUS through MMF using wavefront shaping is developed, and the considerations involved in its design explored. This involves first a number of proof-of-concept experiments, followed by the engineering development needed for a practical imaging system. The effect of interrogating an FPUS through MMF on the sensitivity, resolution and directivity of the sensor is then examined by mapping Ultrasonic (US) fields and imaging known phantoms. Finally, in-vivo imaging is demonstrated using this system. The work presented in this thesis could lead the way to a new class of alloptical US and PAT imaging systems, with applications in areas including endoscopy, handheld imaging and industrial inspection through narrow openings.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Interrogation of Fabry Perot ultrasound sensors through multimode fibre for photoacoustic tomography |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10193117 |
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