Suppression of prepulses by a temporal pulse cleaner based on a self-diffraction process for an ultraintense femtosecond laser

Abstract

In this paper, we suppress prepulses by introducing a temporal pulse cleaner based on a self-diffraction process to an ultraintense and ultrashort chirped-pulse amplification laser facility. The main characteristics of the pulse cleaner are investigated. By optimizing the time delay between two incident pulses and the input energy, the energy of 130 μJ has been achieved for the first-order self-diffraction seed pulse with the maximum conversion efficiency of ∼11%. The spatial beam quality is improved after the pulse cleaner. The first-order self-diffraction seed pulse is stretched, amplified and recompressed by the chirped-pulse amplification technique. The measurement results show that the temporal contrast is improved by more than five orders of magnitude to at least 3 × 1010 for the recompressed first-order self-diffraction pulse when the incident temporal contrast is 1.5 × 105. This enables the laser facility to generate petawatt-class pulses with a nanosecond temporal contrast of higher than 1010.