Absolute laser energy absorption measurement of relativistic 0.7 ps laser pulses in nanowire arrays

Abstract

Laser absorption is one of the most important parameters governing laser–matter interactions. The laser energy absorption on nanowire array targets is measured for the first time in the relativistic regime at intensities of 1019 W/cm2 and compared to foil targets. The results show that the laser energy absorption of 0.7 ps frequency doubled (527 nm) pulses on Au nanowire targets varies widely with nanowire parameters, reaching laser energy absorption values up to ∼71% of the incident energy, significantly exceeding those of solid flat targets obtained in similar irradiation conditions. The analysis shows that the increase in absorption strongly correlates with larger effective target surface area over a broad range of nanowire parameters explored. These direct absorption measurements provide valuable data to benchmark simulations of the relativistic laser pulse interactions with nanostructures.