The effect of time-temperature gradient annealing on microstructure, optical properties and laser-induced damage threshold of TiO2 thin films

The effect of time-temperature gradient annealing on the TiO2 single layers depositing in the same conditions by electron gun were discussed. Investigating the optical properties of the layers which were calculated by envelope method revealed that not only the extinction coefficient but also porous ratio of the layer may affect the laser resistance of the thin films. The experimental results are in a good agreement with theoretical analysis which is based on the well known Yoshida's model. It can be seen the positive impact of higher porous ratio on the laser induced damage threshold values of the TiO2 thin films.In addition, according to the XRD patterns of samples, it can be seen that our novel annealing procedure have a significant influence on the grain size of the TiO2 material. Consequently, comparing the laser induced damage threshold showed that different annealing procedures may modify laser resistance of TiO2 thin films by influencing their optical or structural properties.