Spatio-temporal characterization of double plasma mirror for ultrahigh contrast and stable laser pulse

Abstract

An ultrahigh contrast laser pulse of over 10(11) for 6 ps before the main pulse was achieved by employing a double plasma mirror installed at the end of a 100 TW Ti:sapphire laser system. Spatial beam qualities such as focusability and stability were found to be extremely sensitive in the range of 14-360 J/cm(2) on the double plasma mirror, while ultrahigh contrast was maintained. At the fluence of 90 J/cm(2) the focusability of the ultrahigh contrast laser was not degraded, and the stability was very close to that obtained without the double plasma mirror when the 2-dimensional normalized standard deviation and the correlation function for several laser beam profiles were analyzed. These results are requisites for carrying out relativistic laser-plasma interactions with ultrahigh contrast laser pulses, enabling the use of ultrathin solid targets.