We undertake a wide range of experiments aimed at improving our understanding of the physics of laser-driven accelerators and testing new ideas for improving their operation.
We perform experiments in our labs in Oxford as well as at laboratories elsewhere in Europe and in the USA.
Experimental facilities in Oxford
We have two labs in Oxford devoted to experimental work on plasma accelerators: The TW laser laboratory and the Lasers for Accelerators (L4A) lab.
The TW laser laboratory
The TW laser laboratory comprises: a Ti:sapphire laser oscillator generating 35 fs pulses at a pulse repetition rate of 86 MHz; a pulse stretcher which increases the pulse duration to approximately 300 ps; a 0.7 mJ regenerative amplifier; a multi-pass amplifier, which amplifies the pulse energy to approximately 200 mJ; and a compressor which re-compresses the pulses to approximately 50 fs. Owing to the finite losses in the compressor, the laser pulse energy leaving the compressor is about 200 mJ, i.e. a peak laser power of 2 TW (1 TW = 1012 W); this is almost half the total electrical generating capacity of the planet!
The Oxford TW laser is used to test new designs of plasma waveguide, to test new concepts, and to prepare for our experiments at other laser facilities.
The L4A laboratory
The L4A lab is devoted to research developing fibre lasers for applications in accelerator diagnostics and laser plasma wakefield acceleration. Research in the lab uses a commercial fibre laser CPA system producing ~ 1.5uJ pulses at 6.49MHz which are then used as seed pulses for amplification in photonic crystal fibre, achieving output energies of up to 250uJ. We investigate methods of coherently combining the output of many of these fibres together to produce mJ pulses for multi-pulse laser wakefield acceleration. The lab also has a smaller fibre laser, along with step-index amplifying fibres, for testing novel methods of stabilising trains of laser pulses. More details about the L4A lab can be found here.
Experiments at national and international facilities
Our experiments on particle acceleration are undertaken at laser facilities in the UK, Germany, Sweden, and the USA. We are regularly awarded beam time at the Central Laser Facility's Astra (600 mJ, 40 fs, 15 TW) and Gemini (two beams, each delivering 15 J, 30 fs, 500 TW) lasers.
We have also performed experiments at the Lund Laser Centre, Sweden; Max-Planck-Institut fur Quantenoptik, Germany; and Lawrence Berkeley National Laboratory.