Broadband high-energy mirror for ultrashort pulse amplification system

We report a broadband high-energy mirror for TW-class chirped-pulse amplification of ᄺ-fs pulses. This mirror consists of broadband coatings and optimized high-damage-threshold coatings for decreasing the intensity on the broadband coatings. It is important to optimize the number of high-damage-threshold coatings so that high damage-threshold and relatively low dispersion are traded off against each other. The bandwidth of this mirror ((5겨 nm at 5₀꼀 nm) is almost equivalent to that of a commercial broadband mirror, and the damage threshold of this mirror is almost equivalent to that of a commercial high-energy mirror. This mirror can withstand chirped pulse laser beam's with high fluence (>1 J/cm²) and wide spectra (153 nm FWHM) in practice.