Ultrafast multipulse damage threshold of femtosecond high reflectors.

Laser-induced damage threshold is a fundamental figure of merit of femtosecond optical components used in large-scale laser systems. We tested a series of ultrafast mirrors featuring high band-gap dielectric materials as well as improved design and coating techniques. In a broad range of the damage test pulse train involving between 10 and 100,000 pulses (40 fs, 800 nm), pure dielectric high reflectors exhibit around 1.5  J/cm and hybrid Ag-multilayer mirrors can exhibit well above 1.2  J/cm damage threshold. In addition, a reference antireflection coating exceeded 2  J/cm. Damage threshold dependence on the number of pulses was similar for all optics involved.