Abstract

The development of sub-100-fs chirped pulse amplification (CPA) systems has reached a stage at whiche amplified pulse energies of hundreds of millijoules can be realized, allowing focused intensities to approach 10¹⁹ W/cm² (Refs. 1 and 2). These intensities are currently used in the study of high-harmonic generation in gas jets and of plasma formation in solid or gas targets.^3,4 The efficiency of these phenomena is sensitive to the characteristics of the excitation pulse, particularly for plasma generation, the presence of any pre-pulse or low-intensity pedestal can be seriously detrimental to plasma formation. For CPA it is therefore important to identify the separate contributions to the final pulse pedestal arising from the stretcher/compressor and any initial pedestal structure present in the original seed pulse. Our 2-D ray-tracing analysis of stretcher designs reveals that peak-to-pedestal (PTP) dynamic ranges of >10⁷ are possible Any initial pedestal in the seed pulse from the oscillator must therefore exceed this value.

© 1995 Optical Society of America