Multiterawatt Excimer Laser System

Abstract

A peak power of 4 TW has been obtained in KrF with an output energy of 1.5 J in 390 fs from an electron-beam-pumped amplifier with an active cross section of 320 cm2. The amplified spontaneous emission was as low as 1.8% in energy. The pulse width was measured by the newly-developed third-order autocorrelation technique based on the XeF C-A transition. An initial pulse width of 210 fs was increased to 390 fs through amplifiers. The process of the pulse width broadening was investigated in detail through dummy optics, the thickness of which coinsides with the entire system. The broadening was attributed mainly to the linear dispersion of thick optics for near-transform-limited input pulses. Nonlinear absorption and self-phase modulation were not significant in the output window of a 25-cm-thick CaF2 at an intensity of 13 GW/cm2.