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.

Group webpage

PhD Projects:

High-performance computer simulation of laser-driven coherent X-ray generation for imaging applications

Supervisor:  Dr Peter Horak
Co-supervisor:  Dr Bill Brocklesby

Generation of femtosecond and attosecond X-ray pulses using intense laser pulses has transformed ultrafast science. 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, we will exploit computer simulations to further develop and optimise X-ray sources for coherent imaging, in close collaboration with experimental work already happening in the Ultrafast Laser X-Ray group.

This project will investigate theoretically all effects that contribute to X-ray generation in our setup: the propagation of ultrashort intense laser pulses through a dilute gas, the ionisation of the gas by these pulses, and the interaction of the resulting plasma with the laser and subsequent X-ray radiation generation by atomic recombination. For example, we will look at novel pump lasers and hollow-core optical fibres as gas-filled waveguides and investigate the effects of laser pulse shaping in space and time to optimise the generation of X-rays. 

We will be using a complex computer model that our group has recently developed 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.

Multimode effects in high power fibre lasers and amplifiers

Supervisor:  Dr Peter Horak
Co-supervisor:  Prof. Michalis Zervas

As fibre lasers get more and more powerful, the fibre core size must increase to reduce fibre length, 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-moded or multimoded, optical fibres. We will study the interaction between the active gain medium and the different fibre modes, the coupling of fibre modes by optical nonlinearities such as four-wave-mixing and Raman scattering, and the influence of fibre dispersion on these processes. These numerical and theoretical investigations will be performed in close collaboration with the high-power laser experiments at the ORC and 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. 

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