High energy and high stability optical parametric chirped pulse amplifier for seeding the petawatt beamlines of the Orion laser facility [7721-75]

A high-conversion-efficiency optical parametric chirped-pulse amplifier (OPCPA) with high-energy-stability is demonstrated using lithium triborate (LBO) crystals. Total conversion efficiency of 25% is realised with a net gain of greater than 10. An output energy of ~180mJ at a 2-Hz repetition rate, with a stability of better than 1.5% rms is achieved. The output beam takes the spatial profile of the 20-power super-Gaussian pump beam, whose intensity deviates by less than 7.5% rms over the central 90%. The far-field, whose diameter is near diffraction limited, has a pointing stability of less than one-twelfth of an airy-radius. To the authors’ knowledge this is the first demonstration of an all LBO OPCPA to simultaneously achieve this level of performance.