A team of scientists from the Instituto Superior Tecnico in Lisbon, Imperial College London, and the Universities of St Andrews, Lancaster and Strathclyde as well as STFC’s Central Laser Facility staff have demonstrated the feasibility of a groundbreaking method called Raman amplification which can take long laser pulses and compress them to 1000 times shorter, but with intensities 300 times greater. This means that current very expensive and complex laser set-ups could eventually be replaced with smaller and more cost-effective systems. This would make many technologies, including methods used to develop x-rays which rely on lasers, far more accessible and easier to mass-produce. The next step is to apply the theoretical study on an actual high power laser and fine tune the method through rigorous experimental testing.
The technique has been examined over a two year period, using some of the world’s most powerful supercomputers, to test every possible aspect of the theory. “In the past, studies have been carried out to test the theory, but only using simplified models which do not include all of the relevant phenomena. Our new model has shown that, in most cases, the amplified laser beam breaks up into ‘spikes’, making it difficult to focus the beam to a small spot” said Dr Raoul Trines from STFC’s Central Laser Facility. “But for a few special cases, the amplified laser pulse is of excellent quality, enabling exceptionally tight focusing of the beam”.