Influence of laser wavelength and pulse duration threshold on laser-induced optical damage

A theory based on energy-band is used to study the free electron density in material conductive band and to investigate the interaction of laser and optical material. The relationship between the damage threshold and the laser-wave length, the pulse duration and the band gap is discussed. The influnces of laser wavelength and pulse duration on damage threshold are numerically analyzed. The conclusion shows that, when the pulse duration is shorter than 1 ps, the damage threshold decreases with the increas of pulse duration, while the pulse duration is longer than 1 ps, the damage threshold increases with the increasement of pulse duration, and laser-induced damage threshold in SiO2 decreases with the decreasement of laser wave length in range of 10 fs to 10 ns.