Extreme Physics

When ultra-intense laser pulses interact with dense plasmas, we have shown that it may be possible to accelerate electrons to extraordinarily high energies over the course of several atto-seconds. This process opens up several avenues of research into coherent fast electron creation, coherent x-ray generation, and at ever higher intensities the possibility of measuring QED effects related to positron generation.

The plasma Raman instability can compress existing nanosecond pulse lasers to femtosecond duration. We have found a new amplifier configuration that maximises the output power and reduces requirements on the initial seed laser. The resulting ultra-intense pulses could excite quantum processes such as polarisation of the vacuum.

Classical physics tells us that is impossible for photons in two beams to scatter off one another. Quantum electrodynamics, on the other hand, does allow scattering from the virtual electron-positron pairs when laser beams of sufficient intensity are focused into the vacuum. We are leading an international consortium (Oxford, Imperial College London, Strathclyde, Plymouth, RAL, Gothenburg, Alberta, ShanghaiTech and ELI-NP) to realise this experiment in the laboratory. It might point to new physics ‘beyond the standard model’ of elementary particles.