Temporal contrast in Ti:sapphire lasers: Characterization and control

As ultrafast lasers achieve ever higher focused intensities on target, the problem of ensuring a clean laser-solid interaction becomes more pressing. In this paper, we give concrete examples of the deleterious effects of low-contrast interactions, and address the problem of subpicosecond laser intensity contrast ratio on both characterization and control fronts. We present the new technique of high-dynamic-range plasma-shuttered streak camera contrast measurement, as well as two efficient and relatively inexpensive ways of improving the contrast of short pulse lasers without sacrificing on the output energy: a double-pass Pockels cell (PC), and clean high-energy-pulse seeding of the regenerative amplifier.