Superradiant pulse compression using free-carrier plasma

An alternative approach to pulse compression is discussed. This method utilizes the free-electron plasma as a nonlinear medium for parametric conversion of the energy of a long laser pump into a much shorter (femtoseconds) counter-propagating seed. This originally ultrashort pulse can be amplified by several orders of magnitude over less than a centimeter length of the plasma. There are several advantages in using the free-carrier plasma. First, there is no thermal damage threshold-fresh plasma can be used for each shot. Second, the time response of the plasma is ω_p^-1, which corresponds to 3 fs for n₀=10¹⁹ cm^-3