Professor Giles Davies FREng

Profile

Professional Distinctions

• Royal Society Wolfson Research Merit Award                       2011
• Fellow of the Institute of Physics                                            2012
• Faraday Medal and Prize, The Institute of Physics                2014
• Fellow of the Royal Academy of Engineering                        2016

Responsibilities

• Deputy Executive Dean, Faculty of Engineering and Physical Sciences

Research interests

My early research focussed on the investigation of the optical and electronic properties of low-dimensional correlated electronic systems at millikelvin temperatures, including the use of time-resolved millikelvin magneto-photoluminescence, and single photon counting techniques, to probe the integer and fractional quantum Hall effect ground states of 2D electron and hole systems.  More recently, I have collaboratively developed the field of terahertz frequency electronics and photonics, confronting major international research challenges.

A highlight of our terahertz research includes the demonstration of the first, and long-sought, terahertz frequency quantum cascade laser (QCL) by the EC consortium ‘WANTED’, which has been highlighted by the journal Nature Photonics to be one of the top photonics breakthroughs in the last 50 years.  Working closely with international partners, our subsequent work quickly established the QCL as an intense, precisely controlled source of monochromatic terahertz radiation through: the first demonstrations of continuous-wave operation, and operation at >77 K both pulsed and continuous-wave; the investigation of a range of new active region designs and waveguiding configurations; and, recently, the demonstration of record output powers.

The terahertz QCL is a versatile gain medium for the manipulation and study of fundamental laser operation.  Highlights include the first use of ‘spoof’ surface plasmons and the first use of photonic crystal structures both enabling the emission frequency, beam profile and output power to be engineered. Our recent demonstration of a topologically protected QCL cavity will not only create opportunities for robust device development, but will also provide a platform to explore a better fundamental understanding of topological physics and nonlinear optoelectronics.  By controlling the QCL dynamics at a femtosecond timescale, we achieved the first active mode-locking of a terahertz QCL and coherent detection of the emitted pulse train, the first terahertz pulse amplifier, and the first observation (in any semiconductor laser) of the temporal evolution of the ultrafast switch-on dynamics, laser mode competition and frequency selection.

We recently achieved the first continuous-wave injection locking of a QCL using a near-infrared telecommunications frequency comb. This not only stabilizes the QCL frequency so that it becomes traceable to primary standards, but also significantly reduces the linewidth to <1 Hz, and allows the phase-locked continuous-wave QCL emission to be detected coherently. This brings the frequency precision and accuracy that are available at microwave frequencies to the terahertz region of the spectrum for the first time, and as all components are semiconductor-based, compact integration is possible.

Current funded projects include:

‘TeraCom – Terahertz frequency devices and systems for ultrahigh capacity wireless communications’.  A G Davies, J R Freeman, E H Linfield, J E Cunningham, P Dean, A Valavanis, A Seeds, C Renaud, M Fice, and D A Ritchie.  EPSRC EP/W028921/1, £7,097,283 (1 January 2023 – 31 December 2027).

‘Acoustic control of quantum cascade heterostructures: the THz “S-LASER”’.  J Cunningham, A G Davies, P Dean, E H Linfield, A Valavanis.  EPSRC EP/V004743/1, with EP/V004751/1, £998,934 (1 June 2021–31 May 2024).

‘Coherent pulse propagation and modelocking in terahertz quantum cascade lasers’.  P Dean, D Indjin, J R Freeman, A G Davies, and E H Linfield.  EPSRC EP/T034246/1, £1,127,385 (1 March 2021 – 31 August 2024).

European Commission Horizon 2020 – Future Emerging Technologies.  ‘Extreme Optical Nonlinearities in 2D materials for Far-Infrared Photonics (EXTREME-IR)’.  Project ID: 964735.  S Dhillon, E H Linfield, A G Davies, M Vitiello, and others.  Six groups (universities, research organisations) across Europe; co-ordinated by Centre National de la Recherche Scientifique.  €3,647,533 (total) € 748,946 (Leeds) (1 September 2021 – 28 February 2025).

• Acoustic control of quantum cascade heterostructures: the THz "S-LASER"

Qualifications

• BSc (Honours), First Class, Chemical Physics (University of Bristol, 1987)
• PhD in Semiconductor Physics (University of Cambridge, 1991)

Research groups and institutes

• Pollard Institute
• Terahertz electronics and photonics
• Bio-nanoelectronics

Projects

<li><a href="//phd.leeds.ac.uk/project/1787-terahertz-frequency-devices-for-future-communication-systems">Terahertz frequency devices for future communication systems</a></li>