Grated Compressor Modeling

In order to avoid laser-induced damage to optical components during amplification of a short laser pulse, the pulse often is first stretched in time to reduce its peak power, amplified, and then recompressed. High peak irradiance is attained when the laser beam is subsequently focused onto a laser fusion target. In a laser system, currently under construction, large diffraction gratings will be used in a precise alignment in order to provide pulse compression. Misalignment of the diffraction gratings that comprise the grating compressor can lead to less than optimal pulse compression and reduced ability to focus the beam owing to residual angular dispersion of the pulse spectrum. A computer program was used to model the grating compressor system. The effects of grating alignment errors on the compressed pulse and focused beam were found. A pulse can be broadened from the transform limit of 606 fs to the tolerance limit of 1 ps, by errors in the alignment of diffraction gratings of 75 prad of tilt, 250 prad of tip, 450 prad of rotation, and 6 mm of distance mismatch. The requirement of 80% encircled energy in an area of radius 10 pm is met for all errors corresponding to the 1 ps tolerance limit.