Recent progress in the development of pulse compression gratings
Résumé
A Petawatt facility called PETAL (PETawatt Aquitaine Laser) is under development near the LMJ (Laser MegaJoule) at CEA Cesta, France. PETAL facility uses chirped pulse amplification (CPA) technique. This system needs large pulse compression gratings exhibiting damage threshold of more than 4 J/cm2 in normal beam at 1.053μm and for 500fs pulses. In this paper, we present our recent progress and developments of such pulse compression gratings. We have shown in previous works that the enhancement of the near electric field inside the pillars of the grating drives the damage threshold. This was evidenced from a macroscopic point of view by laser damage testing. We herein demonstrate that damage morphology during damage initiation at the scale of the grating groove is also consistent with this electric field dependence. Some recent grating designs will also be detailed.