Pulse Shaping on the OMEGA Laser System

184 LLE Review, Volume 72 Current target designs for laser-driven inertially confined fusion experiments require that the laser drive pulse be tailored to the target, i.e., that the pulse have some temporal shape other than Gaussian. On the 60-beam OMEGA1 laser system this is accomplished by placing an electro-optic modulator at the input of the system, which is driven by an electrical pulse from a shaped microstrip line. This modulator shapes a 10-ns square optical pulse from a single-mode Nd:YLF laser, which is preamplified in a regenerative amplifier (regen) and then sent through the subsequent OMEGA amplifier chains. Gain saturation in the amplifiers and the presence of the frequencytripling cells cause a significant distortion of the input pulse at the output; however, by modeling these effects we can generally construct a microstrip line that produces a desired output in one pass.