Absolute Laser Energy Absorption Measurement on Nanowire Targets

JAEBUM PARK; RICH LONDON ; REED HOLLINGER ; R. TOMMASINI; CLAYTON BARGSTEN ; VYACHESLAV SHLYAPTSEV; RONNIE SHEPHERD ; MARIA CAPELUTO ; J. J. ROCCA

Conferencia; 62nd Annual Meeting of the APS Division of Plasma Physics. Bulleting of the American Physical Society 65 (11) Monday?Friday; 2020

Laser irradiated nanowire structures can create extreme plasma conditions [1] and substantially increase the laser energy to x-ray conversion efficiency [2]. While the increased laser energy absorption (LEA) by the structured targets [1] is a main contributing factor, there have been no experimental LEA measurements in the relativistic intensity regime (10^18 W/cm2). The LEA by nanowire targets is measured using the frequency-doubled COMET laser at the Jupiter Laser Facility. The results show that the laser energy absorption of 0.7 ps frequency doubled (527 nm) pulses focused to an intensity of 1019 W/cm2 on Au nanowire targets varies with nanowire parameters and reaches up to 71{\%} of the incident energy, greatly exceeding that from foil targets. The absorption is expected to further increase for femtosecond pulses. [1] M. A. Purvis et al., Nature Photonics \textbf{7}, 796 (2013) [2] R. Hollinger et al., Optica \textbf{4}, 1344 (2017)