Automatic phase-locked control of grating tiling

The development of phased-array grating compressor is a crucial issue for the high-energy, ultra-short pulse petawatt-class lasers. Several systems have adopted the tiling-grating approach to meet the size requirements for the compression gratings. Grating tiling need to be precisely phased to ensure a transform-limited focal spot when focusing the high-energy laser pulses onto the target. Monochromatic grating automatic phasing and performance maintaining are experimentally achieved with a far-field CCD camera technique based on a two-tiling system.

► We present the automatic tiled technique based on the far-field focal-spot measurement.
► Relative distance between the focal spot is firstly reduced.
► SPGA algorithm is used to precisely adjust the phase errors.
► Good combined focal spot maintains for hour-long period time.