AUTHOR=Kovács Zsolt , Gilicze Barnabás , Szatmári Sándor , Földes István B. TITLE=Large Spectral Shift of Reflected Radiation From Laser Plasmas Generated by High Contrast KrF Laser Pulses JOURNAL=Frontiers in Physics VOLUME=8 YEAR=2020 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.00321 DOI=10.3389/fphy.2020.00321 ISSN=2296-424X ABSTRACT=

Increasing absorption up to more than 90% with increasing intensity was observed in boron and gold laser plasmas heated by KrF laser pulses of high, but still non-relativistic, intensity. The pulses of 700 fs duration had a temporal contrast of 12 orders of magnitude; thus, the laser pulse of more than 1018 Wcm−2 intensity hit the steep surface of the boron and gold targets. Blue shift of the reflected radiation refers to extreme high acceleration resulting in velocities above 5 × 105 ms−1. Brunel absorption and ponderomotive effects are shown to play an important role in the observed phenomena.