started working on this topic in 2002, when we investigated the use of plasma mirrors as ultrafast self-triggered optical switches [Dou04], to improve the temporal contrast of femtosecond laser pulses by orders of magnitude and avoid the deleterious effect of the temporal pedestal of UHI laser on solid targets [Mon04]. We were the first group to permanently install a double plasma mirror (see picture 1) system for contrast improvement on our TW-class laser [Lev07,Tha07]. We thus routinely obtained temporal contrasts better than 1010 on the 100 ps time-scale, which enabled us to perform some of the first ultrahigh-intensity experiments on solid targets in very well controlled conditions.
Picture 1: picture of a double plasma mirror just after a laser shot. While the plasma surface remains optically flat during a femtosecond laser pulse, and hence does not degrade the laser beam, jets of plasmas and debris are emitted long after this pulse is gone.
[Dou04] Doumy et al, Phys. Rev. E 69, 026402 (2004)
[Lev07] Lévy et al, Optics Letters 32, 3 (2007)