Oxford University physicist pioneers exploration of methods to significantly enhance high-power laser output
Physicists from the University of Oxford in the UK have made breakthrough progress in the field of laser science, demonstrating for the first time a practical technology that significantly enhances the intensity of high-power lasers, and claiming that they "may have created the strongest coherent light source in history".
The results, published in Nature, could open the door to experiments to probe the fundamental laws of physics by directly interacting light with a quantum vacuum. The study involved a broad international collaboration, including researchers from AWE plc, the University of Michigan and the University of Jena.
The work was led by Prof. Peter Norreys and Dr. Robin Timmis at Oxford, working in close collaboration scientists at Queen’s University Belfast and the Science and Technology Facilities Council’s Central Laser Facility (CLF).
Using the Gemini laser at the CLF, the team created extremely bright ultraviolet light through an unusual process. They fired an intense laser at a plasma, causing it to behave like a rapidly moving mirror, in an effect known as relativistic harmonic generation.
Artistic interpretation of coherent harmonic focus generation. The laser is focused on a target and the reflected purple beam forms a CHF of extreme intensity that generates matter from light.
The team also demonstrated a way to concentrate this light even further, in what they call a coherent harmonic focus. In this, many different wavelengths are brought together and focused into an extremely small region, creating a huge concentration of energy.
Lead author Dr. Robin Timmis said, “The discoveries we have made so far are fascinating and it feels like we are just getting started in terms of understanding the rich and complex physics of this mechanism. The simulations suggest that we may have made the most intense source of coherent light ever. I hope we get a chance to return to Gemini soon to confirm this but also to take what we have learnt to larger facilities where we can generate even brighter light.”
The team says that this advance could eventually allow scientists to explore one of the most extreme frontiers of physics: how light and matter interact at the most fundamental level. For instance, it could allow scientists to recreate conditions so extreme that even empty space begins to behave in unusual ways.
At these intensities, light may be able to produce particles directly from the vacuum, offering a way to test long-standing theories about the nature of the universe. This would give researchers a rare opportunity to compare theory with experiment in a completely new regime.
It may even be possible to generate and detect gravitational waves using the coherent harmonic focus, which the researchers aim to explore, as well as testing our understanding of quantum field theory in “never explored regimes”.
The vacuum chamber during the interaction. A relativistically intense laser pulse is focused on the glass target. The interaction generates a green glowing plasma and a purple harmonic beam that contains extreme coherent light fields suitable for quantum vacuum studies.
This work could also help advance laser technologies that can be used right now in industries such as semiconductor manufacturing, while also supporting the longer term goal of building practical fusion energy systems.
Source: optics.org
