400 nm bandwidth ultra-broadband grating stretcher for WNOPCPA prototype facility

The bandwidth broadest grating stretcher with a 400 nm spectrum (covering wavelengths 750–1150 nm) and a 1 ns chirped pulse was developed for the prototype facility of a near-single-cycle petawatt laser project that will use wide-angle non-collinear optical parametric chirped pulse amplification (WNOPCPA). Thanks to the use of self-developed 400 nm bandwidth ultra-broadband gold gratings, the broadest bandwidth of nanosecond-level grating stretchers was dramatically increased from ∼20–200 nm to 400 nm. A few-cycle ultra-broadband seed pulse was temporally stretched with a chirped ratio of 1 ns/400 nm for high-energy amplification. The spectral, temporal, spatial, and importantly spatio-spectral/-temporal characteristics of the output pulsed beam were measured and analyzed. The result could meet the engineering requirements for the WNOPCPA prototype facility and also provide reference value for similar facilities.