High-repetition-rate, diode-pumped multipass preamplifier for the OMEGA master oscillator

Summary form only given. The OMEGA facility is a 60-beam, 30-kJ (UV) laser system for performing inertial confinement fusion (ICF) experiments. One of the main features of the OMEGA laser is an optical pulse-shaping system capable of producing flexible temporal pulse shapes. We present the OMEGA pulse-shaping system layout. The single-frequency OMEGA master oscillator produces long (150-ns FWHM), 1053-nm laser pulses at 300-Hz repetition rate. The sliced out, 20-ns central portion of the pulse has an energy of up to 1 /spl mu/J, which is limited by the damage of cavity components of the master oscillator. The flat-top, 20-ns pulse is then launched into the single-mode optical fiber and split into four OMEGA pulse-shaping channels. Shaped 1- to 3-ns pulses are sent via single-mode fiber to regenerative amplifiers (regens). Due to the losses in launching the fiber, fiber connectors, and pulse shaping modulators, the pulse energy to be injected into a regen is limited to /spl les/0.5 nJ. A high-repetition-rate, diode-pumped preamplifier for the OMEGA master oscillator has been developed to boost the energy of the shaped optical pulses by a factor of 5 to 10.