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John Hadden

Dr John Hadden

Lecturer in Quantum Technologies

School of Engineering

Queen's Buildings - Central Building, Room Room C/3.07, 5 The Parade, Newport Road, Cardiff, CF24 3AA
Available for postgraduate supervision


I am a lecturer at the School of Engineering at Cardiff University. My research focusses on nano-photonics, quantum optics, and quantum sensing technologies based on single photon emitting colour centres in wide bandgap semiconductor materials such as gallium nitride, diamond and 2D materials.

More information can be found on the group webpage.


















My current research interests are in the investigation and development of single photon emitting colour centres for communication and sensing applications in wide band-gap compound semiconductors with mature growth and processing capabilities such as gallium nitride.

My previous work has focussed on the development of colour centres in diamond as photonic quantum technology resources such as single photon quantum emitters and solid state qubits for quantum information.  This involved the coupling of Nitrogen Vacancy (NV) or Silicon Vacancy (SiV) colour centres to photonic structures such as focussed ion beam (FIB) milled solid immersion lenses to improve photon collection efficiency (APL, 97, 24, 241901, 2010), whispering gallery mode microdisk resonators for cavity optomechanics (Optica, 3, 9, 963. 2016), and femtosecond laser written waveguides to guide and collect emitted light (Optics Letters, 43, 15, 3586 2018).

More information can be found on the group webpage.


Following completion of a MSci in Mathematics and Physics at the University of Bristol, I joined the Centre for Quantum Photonics with Profs Jeremy O'Brien and John Rarity, completing a PhD on "Photonic Structures and Techniques for Enhanced Measurement of Spin Qubits in Diamond".  Subsequently I became an Eyes High Postdoctoral Fellow in Prof. Paul Barclay's group at the Institute for Quantum Science and Technology at the University of Calgary.  I joined Cardiff University in 2018, working with Prof. Anthony Bennett and Prof. Diana Huffaker and gaining a Welsh Government funded Sêr Cymru cofund postdoctoral fellowship to support my work on quantum emitters in widebandgap semiconductors.

More information can be found on the group webpage.

Honours and awards

  • 2021-Present Generation Tech (CoI) - Outreach Catalyst Funding - Innovation for All, Research Wales Innovation Funding (RWIF) from the Higher Education Funding Council for Wales (HEFCW).
  • 2019-Present Horizon 2020 Marie Sklodowska-Curie Actions Innovative Training Network - 'Training on Laser Fabrication and Ion Implantation of defects as quantum emitters' - (Co-Author and Named Researcher). (LasIonDef).
  • 2019-2022 Sêr Cymru Cofund Postdoctoral Fellowship - 'NIQuED' - Nitride Integrated Quantum Emitter Devices - PI (2019).
  • 2019-2020 (CoI) EPSRC ECR Institutional Equipment - 'Micro-Raman characterisation system to non-destructively determine the elemental composition of novel materials'.
  • 2019-2020 (PI) Horizon 2020 Marie Sklodowska-Curie Actions Seal of Excellence.

Professional memberships

  • 2015-Present - Institute of Physics.
    • 2021 - Optical group committee - Ordinary member, Acting Secretary.
  • 2020-2021 - Optical Society of America (Optica)

Academic positions

  • 2022 - Current Lecturer in Quantum Technologies, School of Engineering, Cardiff University.
  • 2018 - 2022 Postdoctoral Research Associate/Sêr Cymru Cofund Postdoctoral Fellow, School of Physics and Astronomy, Cardiff University.
  • 2015 - 2018 Eyes High Postdoctoral Fellow, Institute for Quantum Science and Technology, University of Calgary.
  • 2013 - 2014 Posdoctoral Assistant, Centre for Quantum Photonics, School of Physics, University of Bristol.
  • 2008 - 2013 PhD Student, Centre for Quantum Photonics, School of Physics, University of Bristol.

Committees and reviewing


  • Reviewer for journals Nature Communications, Scientific Reports, Laser and Photonics Reviews, PRL, PRA, PRB and APL, and for funding agency EPSRC.


  • 2021-Current IOP Optical group committee - Ordinary member, Acting Secretary.
  • 2018-2022 Organiser of Photonics and Compound Semiconductors Journal Club.
  • 2019-2022 Member of Environment Comittee - School of Physics and Astronomy, Cardiff University.


  • Seeing Single Photons - Development of quantum photonics demonstration experiment for outreach at Cardiff Science festival 2023 - 'The Museum After Dark'
  • Generation Tech - Development of a schools workshop to introduce aspects of compound semiconductor technology and apply them solve real world problems. CoI, scientific advisor and volunteer.
  • STEM Ambassadors Program -  Volunteer at Cardiff science festival events such as ‘The Museum After Dark’, Science Busking, online outreach such as ‘I’m a scientist STAY AT HOME’ and Brightside online STEM ambassadors mentoring.


Interested in supervising and working with students with enthusiasm for their work. Particular interests in 

  • Quantum photonics.
  • Quantum emitters in wide bandgap materials for single photon sources and sensing.

Currently supervising Bilge Yagci and Yanzhao Guo as part of LasIonDef - Training on laser fabrication and ion implantation of defects as quantum emitters.

Research themes


  • Quantum technologies
  • Quantum optics and quantum optomechanics
  • Nanophotonics
  • Compound semiconductors