Recent progress in the development of pulse compression gratings

Abstract

The PETAL facility uses chirped pulse amplification (CPA) technique. This system needs large pulse compression gratings that request damage threshold better than 4 J/cm2 in normal beam at 1.053 μm for 500 fs pulses. In this paper, we will show recent grating designs with either multilayer dielectrics or hybrid metal-dielectric structures. We have shown in previous works that damage threshold is driven by the enhancement of the near electric field inside the pillars of the grating. This was evidenced from a macroscopic point of view by means of laser damage testing. We will show that damage morphology during damage initiation at the scale of the grating groove is also consistent with this electric field dependence.