ИСТИНА

In this work we present our experimental and numerical results on relativistic femtosecond laser-plasma interaction with structured on sub-wavelength scale targets with varied type, size and shape of the modifications. We show that the energy of hot electrons as well as hard X-ray and Gamma generation may be increased up to one order of magnitude for a specific nanostructured target, compared to the interaction with initially flat target. In our experiments we used a laser pulse delivered by the Ti:Sa laser system (pulse duration – 50 fs, energy on target – up to 30 mJ, wavelength – 800 nm, repetition rate – 10 Hz, peak intensity – up to 5x10^18 W/cm^2, contrast on ps timescale >109). The modified targets were prepared via laser ablation, electrochemical etching or deposition of material onto the surface of solids (Si or metals) forming varied types of structures: nanosheres, nanopores, nanograss, foam etc. The main advantages of these techniques is the ability of creating large area sample with very high level of structures reproducibility providing high stability of plasma parameters from shot to shot at high repetition rate of pulses.