Method to realize real-time monitoring and control of a tiled-grating compressor for the XGIII laser facility

In a high-energy chirped-pulse-amplified laser system, grating tiling technology provides an effective means to increase the aperture of the gratings and to scale the energy and irradiance of short-pulse lasers. The difficulties lie in controlling tiling errors accurately between the sub-gratings and keeping long time stability. In this paper, a two-pass full-tiled grating-compressor (TGC) with real- time control unit is developed for the first time. The far-field distributions of the 0th order and -1 st order diffracted beams of the two pairs of tiled gratings are monitored by the same CCD system, with the main laser chain being not disturbed. In this way, we realize online real-time control of tiling errors. Through a method of locking the far-field image to compensating the temporal drift, we can realize the automation of the assembly. The TGC has successfully applied in the multi-function XGIII laser facility, and focusing focal spot and output pulse width are obtained.