Direct measurement of prepulse suppression by use of a plasma shutter

A direct measurement is presented that quantifies prepulse reduction in an intense, ultrashort pulse on reflection from a high-density plasma created from a SiO(2) target at Brewster's angle. The contrast between the intense ultrashort pulse and prepulse energy was improved by a factor of >625. Pulse-width reduction, spectral broadening, and spatial filtering are also observed in the reflected pulse.