Quantum frequency conversion for hybrid quantum networks

About the project

Future quantum networks will need to connect technologies operating at very different wavelengths. This project will develop high-bandwidth quantum frequency converters using four-wave mixing in warm rubidium vapour, translating photons from visible single-photon sources and telecom channels to the near-infrared for direct interfacing with atomic quantum memories.

Future quantum networks will need to connect diverse technologies for generating, transmitting and storing quantum information. A major challenge is that these components often operate at very different optical wavelengths: single-photon sources may emit in the visible, communication channels favour telecom wavelengths, while atomic quantum memories operate at specific near-infrared transitions.

To overcome this challenge, this project will develop high-bandwidth quantum frequency conversion devices using four-wave mixing in warm rubidium vapour. You'll build and investigate two complementary interfaces: converting visible photons (630nm) from hexagonal boron nitride (hBN) single-photon sources and telecom photons (1529nm) from quantum communication channels to the near-infrared (795nm) for interfacing with atomic quantum memories. These interfaces will provide a route to connecting otherwise incompatible quantum technologies within future heterogeneous quantum networks.

You'll gain hands-on experience building atomic physics experiments and laser systems, investigating nonlinear light-matter interactions, and characterising conversion efficiency, bandwidth and noise. You'll progress from continuous-wave spectroscopy to nanosecond optical pulses and ultimately quantum frequency conversion at the single-photon level.

The project forms part of the international AL FreSQO collaboration, bringing opportunities to work with researchers developing hBN single-photon sources, atomic quantum memories and free-space quantum communication links. You'll gain extensive experience in experimental quantum optics, nonlinear optics, atomic physics, lasers, high-speed optical control and single-photon detection. You'll have flexibility to follow your particular research interests, with opportunities to engage with collaborators and industrial partners in the UK and abroad.

Dr Patrick Ledingham PhD

• Quantum light-matter interactions
• Alkali vapour quantum memories
• Rare-earth-ion quantum memories

Entry requirements

You must have at least a UK 2:1 honours degree or its international equivalent .

Fees and funding

Funding is available on a competitive basis through the EPSRC Centre for Doctoral Training in Quantum Technology Engineering at the University of Southampton.

UK students receive a 4 year UKRI TechFirst tax-free stipend of £30,000 per year. Studentships at the UKRI minimum rate are available for EU, Horizon Europe and International students.

Overseas students who have or are seeking external funding are welcome to apply.

While undertaking your research project, you'll also receive substantial training in scientific, technical and commercial skills.

How to apply

Apply now

Please apply via the online portal and select:

Applications should include:

• Academic year: 2027/28
• If you will be full time or part time
• Faculty: Engineering and Physical Sciences
• Search for PhD Quantum Tech Eng
• Add the name of the supervisor in section 2 of the application
• your CV (resumé)
• 2 academic references
• degree transcripts and certificates to date

Faculty of Engineering and Physical Sciences

For questions about applying, email the Centre for Doctoral Training in Quantum Technology Engineering (qte@soton.ac.uk) .

Project leader

For an initial conversation, email Dr Patrick Ledingham (P.Ledingham@soton.ac.uk) .

Research areas