Overcoming acquisition time and resolution limits of photoacoustic imaging using dual comb scanning

This PhD project research investigates a transformative method that employs dual optical frequency combs to overcome the limit due to the wavelength sweeping time. A frequency comb is a light source simultaneously emitting 10s-100s of wavelength tones with equal frequency spacing. By developing a new dual frequency comb and associated real-time signal processing technologies for photoacoustic sensing, we aim to reduce the sensing signal acquisition time by more than two orders of magnitude, enabling fast photoacoustic imaging for wide impact in medicine and disease studies. Our method combines the concept of dual-frequency comb spectroscopy with Fabry-Perot based ultrasound detection for biomedical photoacoustic imaging. Photoacoustic dual-comb multi-heterodyne detection in conjunction with real-time FPGA hardware processing enables the rapid read-out of the sensor with high resolution and precision (traceable to the SI-time standard). Therefore, it allows for a significantly improved signal acquisition time and improved signal to noise ratio.
The student will work with the supervisor on the following subjects:
a) Based on our preliminary studies, further improve the modelling of dual frequency comb approach for photoacoustic imaging, understanding the fundamental acquisition time and signal to noise ratio limits;
b) Carry out experimental studies using the dual-comb system at EEE [5] and the Fabry-Perot ultrasound sensors developed by the photoacoustic group. Further improve the dual comb set up to enable flexibility for different sensors (e.g., sensors with different finesse and thermal stability);
c) Innovate signal processing strategies (e.g., equalizers, calibration algorithms) for fast signal acquisition and improved resolution.
This project will involve both analytical and experimental work, bringing together expertise in optical signal processing and photoacoustic sensing to overcome the time acquisition limit in conventional photoacoustic systems. The new method studied here also allows for an improved SNR for enhanced imaging resolution.

The impact of the CDT in Connected Electronic and Photonic Systems is expected to be wide ranging and include both scientific research and industry outcomes. In terms of academia, it is envisaged that there will be a growing range of research activity in this converged field in coming years, and so the research students should not only have opportunities to continue their work as research fellows, but also to increasingly find posts as academics and indeed in policy advice and consulting.

The main area of impact, however, is expected to be industrial manufacturing and service industries. Relevant industries will include those involved in all areas of Information and Communication Technologies (ICT), together with printing, consumer electronics, construction, infrastructure, defence, energy, engineering, security, medicine and indeed systems companies providing information systems, for example for the financial, retail and medical sectors. Such industries will be at the heart of the digital economy, energy, healthcare, security and manufacturing fields. These industries have huge markets, for example the global consumer electronics market is expected to reach $2.97 trillion in 2020. The photonics sector itself represents a huge enterprise. The global photonics market was $510B in 2013 and is expected to grow to $766 billion in 2020. The UK has the fifth largest manufacturing base in electronics in the world, with annual turnover of £78 billion and employing 800,000 people (TechUK 2016). The UK photonics industry is also world leading with annual turnover of over £10.5 billion, employing 70,000 people and showing sustained growth of 6% to 8% per year over the last three decades (Hansard, 25 January 2017 Col. 122WH). As well as involving large companies, such as Airbus, Leonardo and ARM, there are over 10,000 UK SMEs in the electronics and photonics manufacturing sector, according to Innovate UK. Evidence of the entrepreneurial culture that exists and the potential for benefit to the UK economy from establishing the CDT includes the founding of companies such as Smart Holograms, PervasID, Light Blue Optics, Zinwave, Eight19 and Photon Design by staff and our former PhD students. Indeed, over 20 companies have been spun out in the last 10 years from the groups proposing this CDT.

The success of these industries has depended upon the availability of highly skilled researchers to drive innovation and competitive edge. 70% of survey respondents in the Hennik Annual Manufacturing Report 2017 reported difficulty in recruiting suitably skilled workers. Contributing to meeting this acute need will be the primary impact of the CEPS CDT.

Centre research activities will contribute very strongly to research impact in the ICT area (Internet of Things (IoT), data centre interconnects, next generation access technologies, 5G+ network backhaul, converged photonic/electronic integration, quantum information processing etc), underpinning the Information and Communications Technologies (ICT) and Digital Economy themes and contributing strongly to the themes of Energy (low energy lighting, low energy large area photonic/electronics for e-posters and window shading, photovoltaics, energy efficient displays), Manufacturing the Future (integrated photonic and electronic circuits, smart materials processing with photonics, embedded intelligence and interconnects for Industry 4.0), Quantum Technologies (device and systems integration for quantum communications and information processing) Healthcare Technologies (optical coherence tomography, discrete and real time biosensing, personalised healthcare), Global Uncertainties and Living with Environmental Change (resilient converged communications, advanced sensing systems incorporating electronics with photonics).