Abstract

We report on the recent progress in the contrast campaign for Astra-Gemini laser. An extensive experimental study shows that the main contributions to the “coherent” contrast feature come from the stretcher gratings. Implementing higher-quality gratings resulted in a significant contrast enhancement. Further enhancement by 4 orders of magnitude was also demonstrated using double plasma mirrors (DPM). In addition, the replica prepulses were greatly suppressed or eliminated by employing the wedged crystals and optics, providing a very clean laser pulse.

© 2012 Optical Society of America