Wave-front reconstruction and analysis of far-field high-order harmonics from relativistic plasma surfaces

With a numerical reconstruction algorithm proposed, the complete far-field wave-fronts of harmonics, which are emitted from relativistic plasma surfaces, have been retrieved from their complex spatial-temporal distributions. Combining theoretical analysis and three-dimensional simulations, the impact of the plasma density gradient, driving pulse quality, and polarization have been comprehensively investigated. Abundant information on the generation mechanism, optical properties, and aberration evolution of the generated harmonics, as well as the relativistic plasma surface structure are decoded from the reconstructed wave-front. Furthermore, proper defocusing incident lasers are proposed to achieve aberration-free attosecond sources at the extreme ultraviolet region with Gaussian-like intensity distribution. Providing powerful numerical tools and practical advice, current work is essential for analyzing wave-fronts, studying relativistic plasma properties and utilizing attosecond pulses in ultrafast metrology and control.