Proposed beatwave experiment at RAL with the Vulcan CPA laser

A chirped pulse amplification (CPA) laser configuration capable of driving a plasma beat wave into saturation before modulation instabilities can grow is reported. The proposal is based on generating a single sub-ps, broad bandwidth pulse (/spl sim/16 nm) and stretching and filtering to select two wavelength components (separation /spl sim/7 nm). The two spectral components are temporally stretched (to >100 ps) and separated (by /spl sim/1 ns). The pulses are then amplified sequentially in a single Nd:glass chain to greater than 15 J per pulse. Using a single-pass reflective grating compressor, the pulses are compressed (from 2 to 5 ps) and automatically synchronized. The system is capable of introducing a chirp, such that the compressed pulses can compensate for relativistic detuning of the plasma wave. The optimum laser amplification and recombination configuration for generating a saturated laser-driven beatwave is presented, and options for future work are discussed.