Recent development of the high-power chirpedpulse amplification (CPA) laser system has made the intensities ＞1020W.cm-2.[1] For such high intensities,pulse contrast better than 109 is necessary to avoid pre-plasma in the laser-matter interactions,[2]which challenges both the pulse-cleaning and diagnostic techniques.Pulse-contrast diagnostic techniques are mainly based on nonlinear cross-correlation,in which a clean sampling pulse is typically obtained by second-harmonic generation (SHG) or optical parametric amplification (OPA) of the pulse under test.[3,4]Commercialized time-scanning cross-correlators with dynamic range about 1011 have been widely used to diagnose high-repetition-rate CPA lasers.[3] However,for most of the high-intensity CPA laser systems,which are currently operated at low repetitions or even nonrepetitively,[5,6] it is necessary to develop pulse diagnostic technologies operating in single-shot mode.