Abstract

In many applications of high-intensity, short-pulse lasers, such as x-ray generation, it is important to have a high-contrast, ultrafast pulse. Chirped-pulse-amplification (CPA) lasers have already reached intensities of 10¹⁹ to 10²⁰ W/cm². Under these conditions, a minimum peak-to-pedestal contrast of 10⁸ to 10⁹ is required to avoid preionizing a solid target before the main peak of the pulse arrives. For Nd:glass CPA systems utilizing a fiber, the compressed pulse has a contrast between 10²:1 and 10³:1 and is not directly suited for such experiments.^1,2 We have considered the pedestal originating from the oscillator, fiber, and amplified spontaneous emission (ASE) of the regenerative amplifier and the subsequent suppression of it by optical pulse cleaning (OPC) before amplification and by a saturable absorber after it.

© 1995 Optical Society of America