Contrast Improvement of Relativistic Few-Cycle Light Pulses

摘要: Laser-plasma interaction has been a widespread and popular field of research since the birth laser. It involves numerous interesting phenomena such as inertial confinement fusion; generation acceleration electron, positron, neutron, proton ion particle beams; source electro-magnetic radiation in IR, visible, UV x-ray range, just to mention some important applications. The continuously increasing power development chirped pulse amplification lead electric fields which oscillating free electrons reach almost speed light. This so called relativistic optics regime starts at intensities about 1018 W/cm2 1 μm wavelength. relativistically intense laser pulses with solid state -possibly liquidtarget material is always accompanied by creation inhomogeneous plasmas, given amount extended preplasma formed front target before main arrives. produced undesired light impinging onto short pulse. Its density decreases rapidly farther from due hydrodynamic expansion hot plasma during time till comes. extension significantly influences leads completely different types processes depending on its value. Typical lasers produce an pulse, because they amplify preand postpulses pedestals various origins. Therefore certain involving low plasmas dominate these investigations. On other hand, practically preplasma-free environment required laser-plasma experiments ultra-intense high-density like surface high harmonic Monot et al. (2004); Thaury (2007), laser-driven Hegelich (2006) or few nanometer thick diamond-like-carbon foils, nanofoils. formation influenced contrast, characterizes intensity after relative this precise characterization improvement contrast are essential successfully conduct experiments. Laser duration only optical cycles moderate opened up new era attosecond physics Brabec & Krausz (2000); Ivanov (2009) via controlled reproducible weak XUV hundred(s) attoseconds precisely synchronized These allow investigation electron motion atoms, molecules states pump visible / near infrared probe configuration. Relativistic few-cycle sources hold promise generate unprecedented energy thus form basis novel 14