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The Laser Integration Line (LIL) was first designed as a prototype to validate the concepts and the laser architecture of the Laser MegaJoule (LMJ). The LIL facility is a 4-beam laser representing a quad structure of the LMJ. A set of test campaigns were conducted to safely ramp up laser performance. The main goal was to measure quad-specific features such as beam synchronization and focal spot (size, smoothing contrast ratio or irradiation nonuniformity) versus the LMJ requirements. Following the laser commissioning, the LIL has become a major instrument dedicated to the achievement of plasma physics experiments for the French Simulation Program and was also opened to the academic scientific community. One of the attributes of the LIL facility is to be very flexible to accommodate the requests of plasma physicists during campaigns. The LIL is constantly evolving to best meet the needs of target physicists. Changes made or planned are either to improve the quality of laser beams, or to increase the LIL Energy-Power operating space. To optimize preparation and design of shot campaigns, the LIL performance status has been elaborated. It gives information about the characteristics of the laser in terms of near field and far field, defines the steps to maintain performance, explains how the facility responds to the request, details settings (smoothing, shaping of the focal spot, energy, temporal pulse shaping, beam pointing) and gives the limits in energy and power. In this paper, an overview of the LIL performance is presented.

The Nd-glass Phebus laser has the capability of delivering 2 X 10 kJ in a 1.3 ns pulse when using the usual narrow band oscillator. For the purpose of focal spot smoothing the coherence of the pulse is reduced by injecting the beam of a 1 nm bandwidth oscillator into a step index optical fiber. The use of the optical fiber at the laser front end changes the common point laser source into an extended source. The required optical arrangement taking into account the divergence of the extended source beam is described. The smoothing efficiency is measured by the reduction of one order of magnitude of the contrast of the energy modulations in the focal spot. It is experimentally established that non linear effects limit the power density in the amplifying medium to a value depending on the geometrical extension of the source. The identification of the relevant non linear effects is discussed.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The PHEBUS facility has operated since 1986 for the French laser matter interaction program at Limeil. The performances of this system, which is the third most powerful one in the world, are presented as well as some new developments which aim at smoothing the laser beam in order to improve the overall laser-target behavior.

This facility has been operated since 1986 for the French laser matter interaction program at Limeil. It is the third most powerful laser system in the world. We will emphasize in this presentation the 1.06 micron performances of the facility, although it is mainly aimed at working for .53 and .35 micron plasma experiments1.