The University of Southampton

Computational Nonlinear Optics

The Computational Nonlinear Optics group is developing theoretical and numerical models for a wide range of photonics systems, from single-quantum interactions in optical resonators to high-power laser propagation in fibres. 

This work is supporting various experimental and fabrication activities across the ORC with the aim to identify and explore underlying nonlinear and quantum optical phenomena as well as material and structural effects. The results find applications in novel and improved short-pulse lasers, frequency converters, sensors, microstructured fibres, telecom systems, and even quantum logic circuits.

All PhD Projects: 

  • Funding: For UK students, tuition fees and a stipend at the UKRI rate plus £2,000 ORC enhancement tax-free per annum for up to 3.5 years (totalling around £21,000 for 2024/25, rising annually). EU and Horizon Europe students are eligible for scholarships. CSC students are eligible for fee waivers. Funding for other international applicants is very limited and highly competitive. Overseas students who have secured or are seeking external funding are welcome to apply.
  • Entry requirements. Applicants should have a first class or a good upper-second class degree (or the equivalent) in physics, engineering or a related discipline.
  • Closing date: Applications are accepted throughout the year. The start date will typically be late September, but other dates are possible.
  • Apply online here.


PhD Projects:

Spatial effects in high-power fibre lasers and amplifiers

Supervisory Team: Dr Peter HorakProf Michalis Zervas

We are looking for a PhD student to work on the design and numerical simulation of the next generation of high-power fibre lasers. The project is part of a major new initiative funded by the UK Research Council at the Optoelectronics Research Centre, University of Southampton, that will combine new fibre technology with state-of-the-art control mechanisms, including machine learning, to reach unprecedented laser powers with full control over the beam shape. 

As fibre lasers get more and more powerful, the fibre core size must increase to minimise optical nonlinearities and avoid material damage. This adds spatial degrees of freedom to the laser beam that have to be controlled in order to obtain a clean, well-behaved laser output. This project will exploit computer simulations to investigate the dynamics of the generation of light in such large, few-mode or multimode, optical fibres. We will analyse the dynamics of the spatial light profile and its dependence on the gain medium, fibre losses, optical nonlinearities, chromatic dispersion, and thermal and acoustic effects. These numerical and theoretical investigations will be performed in close collaboration with corresponding high-power laser experiments in our labs and at our industrial partners. 

If you have an interest in computational physics and research in the exciting area of high-power lasers, you would be highly suitable for this project. You will benefit from our world-leading expertise in these fields and exploit state-of-the-art computer hardware for your research on a PhD project which is highly relevant for the future development of the next generation of fibre lasers and their applications in, for example, advanced digital manufacturing and medical surgery.


High-performance computer simulation of laser-driven X-ray microscopy

Supervisory Team: Dr Peter HorakDr Bill Brocklesby

We are looking for a PhD student to join our interdisciplinary team of students, postdocs, and senior researchers with backgrounds in physics, chemistry, and engineering, to work on the development of a new femtosecond laser-based source of X-ray pulses approaching the attosecond regime (less than a millionth of a billionth of a second long).  

Generation of such femtosecond and attosecond X-ray pulses using intense laser pulses has transformed ultrafast science, as recognised by the 2023 Nobel Prize in Physics. The ability to produce coherent ultrafast X-ray pulses has applications in many areas, from the investigation of ultrafast molecular dynamics to biomedical imaging. In this PhD project you will exploit computer simulations to develop sources for X-ray microscopy which will be realised in our labs at the University of Southampton and at the Rosalind Franklin Institute at the Rutherford Appleton Laboratories, near Oxford.  

New femtosecond fibre laser-based ultrafast pulse sources and novel hollow-core optical fibres have the potential to produce brighter and shorter-wavelength X-ray pulses. The project will investigate theoretically and numerically how these new sources can be developed and optimised, in parallel with the experimental work in our labs. You will investigate all effects that contribute to X-ray emission by high-harmonic generation, including propagation of ultrashort intense laser pulses through a dilute gas, ionisation of the gas by these pulses, the interaction of the resulting plasma with the laser, and the subsequent X-ray emission by atomic recombination.  

You will be developing the comprehensive computer model used within our group as the basis for this project. The code is written in C++ and Python and runs on the Southampton supercomputer cluster Iridis. The project is therefore best suited for a student with a strong interest in programming and high-performance computing as well as a background in physics, nonlinear optics and/or lasers. You will benefit from the world-leading expertise in these fields by your collaborators and work in a supportive group of like-minded researchers, leading you to a PhD in an exciting new area of physics and technology.


Chip-based photonic devices for quantum technology

Supervisory Team: Dr Peter HorakDr James Gates

We are looking for a PhD student to join our interdisciplinary team of students, postdocs, and senior researchers developing chip-based, microscale optics for advancing quantum technologies.  

Many quantum technologies, such as quantum computing, quantum communication, and quantum sensing, often rely on optics for the preparation, transmission, and read-out of quantum states. If we want to scale up the quantum information processing power of these devices, we therefore need to integrate a range of optical components onto the chip.  

In this project you will contribute to the design and numerical simulation of advanced photonic devices tailored for quantum applications, working in close collaboration with fabricators and experimentalists. If you are interested in a PhD combining computer modelling and lab work and have the required skills, the project can also be adjusted for this. Potential areas of research include:  

-       Integrated optical waveguides and large area Bragg gratings: Investigate the incorporation of tilted Bragg gratings to couple light out of integrated waveguides and form beams of well-defined shape and polarisation for interaction with stationary trapped quantum particles (e.g. atoms or ions). The light can be used to laser cool the particles and/or for optical manipulation of their internal quantum states.

-       Integrated photon collectors: Similar devices as above can be designed to collect photons emitted from trapped particles, either to read out their quantum state, or for coupling photons into optical fibres for long-distance transmission and the generation of remote quantum entanglement.

-       Freeform micro-optics: Develop innovative freeform micro-optic lenses, mirrors, and resonators for enhanced beam shaping, enabling the creation of more compact and more efficient quantum photonic systems.  

If you have an interest in photonics, quantum technology, and computer-based modelling, you would be highly suitable for this project. You will benefit from our world-leading expertise in these fields and enjoy working in a highly supportive environment in our group in Southampton and collaboration with partner groups around the country within the UK National Quantum Technology Programme.


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