Improved damage threshold and diffraction efficiency of gratings for ultra-bright lasers in sub-picosecond regime

• Main Authors: Wattellier, B., Zou, J.P., Sauteret, C., Migus, A., Blanchot, N., Baures, P.-Y., Husson, D., Bercegol, H., Reichart, A., Bonnemason, F., Flamand, J., Touzet, B., Neuviere, P.
• Format: Conference Proceeding
• Language: English
• Subjects: Chirp; Dielectric materials; Diffraction gratings; Dispersion; Etching; Optical diffraction; Optical propagation; Optical pulses; Pulse amplifiers; Stimulated emission
• DOI: 10.1109/CLEO.2001.947531

Summary form only given. For the last 15 years, diffraction gratings have been the key critical components of the chirped pulse amplification (CPA) technique. They can introduce a large dispersion on an optical short pulse without propagating through a dispersive medium. However, their limited damage threshold has led to limited compressed energy. Furthermore, all present diffraction gratings used in CPA laser chains have a limited diffraction efficiency (typically 60% in it four-'pass scheme). Current diffraction gratings are made by etching a silicate substrate before evaporating a thin gold layer on the top. This means that the diffraction occurs at the surface. The energy is thus concentrated in a very thin layer. Consequently, a way to improve the damage threshold is to let the electro-magnetic field diffract in the material bulk, for instance, in a multi-layer dielectric material. The grooves of the diffraction gratings can be produced by ion-etching dielectric coated mirrors.