Wave front correction and second harmonic generation of a CPA terawatt laser chain

Summary form only given. High peak-power lasers, using the chirped pulse amplification (CPA) technique, now routinely achieve the terawatt level and generate focused intensities in the 10/sup 18/-10/sup 19/ W/cm/sup 2/ range. For many laser-matter interaction experiments, especially those involving solid targets, a high peak-to-background contrast, a high intensity and a well-characterized focal spot are necessary. During the amplification process, wave front distortions appear due mainly to thermal effects in the amplification media and imperfections of large optics. These distortions lead to a broader focus spot and a loss in terms of focused intensity. Amplified Spontaneous Emission (ASE) limits the pulse contrast in CPA lasers. By combining wave front correction, high aperture parabola and second harmonic generation we obtain a high-contrast beam with a high focused intensity.