Advanced Solid State Sources and Applications

The group currently has vacancies for new students in the following research areas:

This project will focus primarily on broadband superfluorescent fibre sources operating in cw and pulsed modes at very high average power levels (i.e. ~ 100W and above). This is an area which so far seems to have been largely overlooked by those working in the area of high power lasers in spite of the fact that there are a huge range of potential applications and some very interesting physics behind these sources. The project will investigate various superfluorescent source configurations (based on novel double-clad fibre designs) with a view to understanding the relevant physics and establishing a strategy for power scaling and controlling the spectral characteristics. In addition, we will also investigate some of the applications of these sources including low coherence interferometry and nonlinear frequency conversion schemes for broadband sources.

This project will investigate laser cooling of various rare-earth ion doped materials using novel pumping schemes and very high power fibre pump sources. Radiation cooling by anti-Stokes fluorescence was first demonstrated in 1995 and has attracted a great deal of interest. The basic idea is to absorb light (i.e. from a ‘pump’ laser) on the long wavelength (i.e. low energy) side of a material’s absorption spectrum followed by very rapid thermalisation (i.e. re-establishment of thermal equilibrium) and then re-emission of fluorescence at shorter wavelengths (i.e. higher energies) on average. This allows vibration-free cooling of very small samples of material with a range of potential applications. However, there are a number of challenges and as a result progress in cooling to low temperatures has been rather slow. Nevertheless, the potential of this approach is enormous and, in principle, very low temperatures are achievable. One of the issues is the pump laser. This should provide high output power, good beam quality and have flexibility in the operating wavelength. Our plan is to exploit the advantages of a special design of cladding-pumped fibre source with a number of additional novel features (e.g. pumping scheme configuration) to achieve much lower temperatures than have been achieved before via this technique and, hopefully, to explore the physical limits of the approach. The project will be quite challenging, but will also be very rewarding in the sense that it will open up many new possibilities.

This project will investigate power scaling of lasers by combining the advantages of cladding-pumped fibre and bulk solid-state lasers in the form of a hybrid laser operating at low temperatures. A particular attraction of this approach is that it offers a route to much higher pulse energies than can be achieved using conventional solid-state laser or fibre laser geometries. Operation of solid-state lasers at very low temperature is a very attractive way to reduce to thermal effects and has attracted growing interest within the laser community over the last few years. The use of this approach in combination with a hybrid laser configuration should offer unprecedented levels of performance, but has so far not been explored. The main ambition of our project is to conduct this study with a view to demonstrating high power lasers with unrivalled performance in the eyesafe wavelength regimes around 1.6 and 2 microns.

For a full list of PhD projects available at the ORC click here.