Laser beams can be strongly compressed in a plasma by stimulated Raman backscattering in a time short compared to the time scale for filamentation instabilities to develop. Such a compression should make feasible multi-MJ multi-exawatt-laser pulses technologically challenging by other means. The compression efficiency can reach nearly $100\%$ at the Langmuir wave breaking limit.

• Received 14 December 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.4448