Main Research Projects:

High-Speed, Multi-Channel, Parallel Data Acquisition for Chemical Species Tomography of Jet-Engines:

  • EPSRC FLITES Grant, Post-Doctoral Research Associate (PDRA) under Prof. Hugh McCann

    • The Fibre-Laser Imaging of gas Turbine Exhaust Species (FLITES) aimed to utilise tunable diode lasers to implement wavelength-modulation gas spectroscopy for a regular grid of 126 laser beams. These beams crossed the exhaust plume region of large Rolls-Royce commercial jet-engines such as the Trent XWB. The spectroscopy can be tailored to specific gases and the resulting data can be used to tomographically calculate an image. This process is called chemical species tomography (CST) and can target gases such as Carbon Dioxide, Carbon Monoxide, Water Vapour, the oxides of nitrogen and sulphur and small-chain unburnt-fuel hydrocarbons.

    • To enable this the single-beam data acquisition hardware needed to be re-designed with a view to a massively parallel, high-speed topology that would be suitable for the spectroscopy and the harsh environment of a test cell.

    • Data acquisition is a well-researched area, however, a central theme is how to obtain highly reliable (low-noise) experimental data, in a highly scalable manner and to optimally compute some of the complex data that is required by the gas spectroscopy.

    • Funding: Engineering and Physical Sciences Research Council (EPSRC) - Grant EP/J002151/2

    • Publications: Funded via EPSRC - [See Here]

    • Collaborators: The University of Edinburgh, The University of Strathclyde, The University of Manchester, The University of Southampton, Rolls-Royce, Instituto Nacional de Técnica Aeroespacial (INTA), Royal Dutch Shell, OptoSci, CEMAT and other SMEs.

    • Active Years: 2013 to 2019

The History, Literature and Development of Silicon Avalanche and Geiger-Mode Photodiodes

  • Unfunded, Independent Research

    • Single-photon avalanche diodes (SPADs), avalanche photodiodes (APDs) and other single-photon detectors are now being used for systems such as LIDAR in self-driving cars, 3D and time-of-flight (ToF) cameras, high-sensitivity spectrometers, novel positron emission tomography (PET) scanners and even brain-scanners utilising cranial near-infrared absorption spectroscopy (C-NIRS). However, few researchers have the time to conduct a robust historical literature review. This results in literature reviews that are sparse, show bias towards already highly-cited literature and over a relatively short period. A researcher writing in 2020 may only go back to 1990.

    • But... the historical development of SPADs and all devices that use the avalanche multiplication of electrons is of interest to the wider field. In this independent research project, I undertook a full literature review for the years 1900 to 1969. Rather than selecting the most cited papers, it was crucial to reference all papers relevant to these devices. The manuscript - [published here] - represents a de-facto literature review for these devices. 

    • This historical analysis is currently being extended backwards to cover more of the period of 1860 to 1910 and is slowly being extended through the 1970s, 80s and 90s. However, the volume of literature for the 1970s alone outstrips the entire literature for the 1900 to 1969 period.

    • Funding: Self-funded using personal finances.

    • Publications: Open-Access funded via The University of Edinburgh - [See Here]

    • Collaborators: None (fully independent).

    • Active Years: 2016 to 2018

CMOS Single-Photon Avalanche Diode (SPAD) Arrays with Reconfigurable Digital Readout Structures:

  • EPSRC HYPIX Grant, Doctoral Candidate (Ph.D.) under Prof. Robert Henderson and Prof. Ian Underwood

    • The HYPIX project aimed to integrate Silicon-CMOS driving electronics, Ga-N micro-LED structures, lasing organic polymers and lithographic features into a 2.5D optical stack. The key was to use the micro-LED structures to optically pump the organic polymers, with automatic feedback as to the LED brightness such that the Laser light was well controlled. 

    • While this was blue-sky in its initial approach, there was a distinct idea for this to be applied to visible light communications (VLC), whereby an addressable array of 32x32 micro-LEDs could pump pixelated regions of the lasing polymer producing a large set (1024) of distinct optical data channels.

    • To complement such a transmitter, an array of 32x32 SPADs was produced as a receiver prototype and as a testing harness for high-sensitivity optical studies of the lasing polymer. The result was a receiver able to offer multiple reception modes, single-photon sensitivity and a variety of high-speed readout structures. 

    • Subsequent research showed that the dead-time of SPADs produces its own effect on the receiver transient behaviour (impulse and step responses) and that the number and management of diodes connected in parallel could be used to reduce the negative impact of the dead-time.

    • Funding: Engineering and Physical Sciences Research Council (EPSRC) - Grant EP/F060076/1

    • Publications: Funded via EPSRC and open-access via The University of Edinburgh - [See Here]

    • Collaborators: The University of Edinburgh, The University of Strathclyde, The University of St Andrews, Imperial College London.

    • Active Years: 2009 to 2012, 2016