Analysis in wavelength dependence of electronic damage

Many investigations in laser induced damage thresholds (LIDT) have shown a very deterministic behavior for the ultra short pulse regime. From the current understanding, femtosecond laser damage is driven by electronic photon-matter interaction. This process can be theoretically described by photo-, and avalanche-ionization and the respective relaxation processes. On the basis of a wavelength dependency of the laser-induced damage threshold of titania, a dominant influence of multi-photon absorption (MPI) on the damage behavior could be demonstrated. This particular characteristic could be observed in a stepwise increase of the LIDT in the transition ranges of the orders of multi-photon absorption. This paper presents an analysis of the wavelength dependence of femtosecond LIDT with different theoretic models and a comparison of simulated data with the measured wavelength dependence of titania. Both, the wavelength position and the quantitative change of the laser power resistance in the range of the n to the n+1 photon absorption are calculated in a theoretical analysis. Additionally, the influence of different microstructures of titania on the quantized MPIcharacteristic is investigated.