Multiterawatt excimer-laser system

A peak power of 4 TW has been obtained in KrF with an output energy of 1.5 J in 390 fsec from an electron-beam-pumped amplifier. The energy of the amplified spontaneous emission was as low as 1.8%. The pulse width was measured by the newly developed third-order autocorrelation technique based on the XeF C–A transition. Amplifiers increased the initial pulse width of 210 fsec to 390 fsec. The process of pulse-width broadening was investigated in detail. It was confirmed that the two-photon process contributes to small absorption in CaF2 by the luminescence of self-trapped excitons. A terawatt-class KrF laser system with a moderate repetition rate was developed for applications to multiphoton processes.