  Raman amplification in plasma has been promoted as a means of compressing
picosecond optical laser pulses to femtosecond duration to explore the
intensity frontier. Here we show for the first time that it can be used, with
equal success, to compress laser pulses from nanosecond to picosecond duration.
Simulations show up to 60% energy transfer from pump to probe pulses, implying
that multi-kiloJoule ultra-violet petawatt laser pulses can be produced using
this scheme. This has important consequences for the demonstration of
fast-ignition inertial confinement fusion.
