A High-energy, High-average-power Laser Using Nd:ylf Rods Corrected by Magnetorheological Finishing

194 LLE Review, Volume 99 Introduction Optical parametric chirped-pulse amplification1,2 (OPCPA) is well suited for the front end of modern petawatt glass laser chains.3 The broadband gain available with OPCPA at a wavelength of 1053 nm offsets the gain narrowing that occurs in large Nd-doped glass amplifiers.4 It can be scaled to large energies,5 in contrast to the practical limits imposed by the mode volume of a laser cavity in regenerative amplification. Lastly, the OPCPA process is prepulse free6 and can produce gains of up to 109 using a relatively simple optical system, which minimizes beam distortions.