Argus laser

Argus was a two-beam high power infrared neodymium doped silica glass laser with a 20 cm (7.9 in) output aperture built at Lawrence Livermore National Laboratory in 1976 for the study of inertial confinement fusion.

It was known from some of the earlier experiments in ICF that when large laser systems amplified their beams beyond a certain point (typically around the gigawatt level), nonlinear optical effects would begin to appear due to the very intense nature of the light.

In order to improve the quality of the amplified beams, LLNL had started experimenting with the use of spatial filters in the single-beam Cyclops laser, built the previous year.

The basic idea was to extend the laser device into a very long "beamline", over which any imperfections that accumulated in the beam would be successively removed after every amplification stage.

Argus used a series of five groups of amplifiers and spatial filters arranged along the beamlines, each one boosting power until it reached a total of about 1 kilojoule and 1-2 terawatts per beam.