In the highest-power chirped-pulse amplification lasers,the pulse must be stretched in time,amplified,compressed in a grating compressor and subsequently focused by off-axis parabola to obtain a high peak power.In the optical terminal,the temporal and spatial effects of mismatched multigrating tiled compressor on the far-field pulse are critical factors to be analysed.In this paper,a k-space raytracing model is proposed for the temporal and spatial analyses of possible errors in a four-grating single-pass tiled compressor.The results show that the last grating affects mainly the partial focal spot,while the middle two gratings affect the temporal waveform,and the partial focal spot needs much higher error control than that in the temporal domain in a picosecond pulse compression.
The development of phased-array grating compressor is a crucial issue for high-energy,ultra-short pulse petawatt-class lasers.Almost all systems have adopted a tiled-grating approach to meet the size requirements for the compression gratings.We present a computer-control test system utilizing near-field interference and far-field focusing capable of monitoring and fast correcting tiled errors of the grating compressor.In this system,the tilt/tip errors between the two gratings are determined by the Fourier transform (FT) of the individual interference fringe,and the piston errors are determined by the ratio of the two primary peaks formed in the far-field pattern as a function of the piston difference.Monochromatic grating phasing is achieved experimentally and pulse compression is demonstrated with a tiled grating system.
