| Abstract [eng] |
Polishing and grinding induced contamination remains the key limitation for resistance against surface damage, particularly at UV range. Nano-defects and nano-absorbing particles near the surface of optic materials can initiate breakdown at fluencies and intensities far below the intrinsic damage threshold. Thus, careful characterization of defects properties and distribution is needed in order to improve any of manufacturing step. In this work, two techniques for determination of existing defect ensemble on fused silica sample were used, namely damage probability and raster scan. Several different mathematical models quantifying possible defect ensembles are analyzed – degenerate, power law and Gaussian law. The aim – to investigate whether both techniques – damage probability and raster scan – are capable to describe and quantify true defect ensemble on fused silica sample exposed by UV light. It was shown that power law is the most feasible model to reproduce experimental data in both raster scan and damage probability techniques. In contrast to degenerate and Gaussian models, power law reveals highest value of likelihood function in damage probability method and fits experimental data of damage density best in raster scan measurements. However, parameters of empirical function depend on measurement method, thus any of the models can tell what the true defect ensemble is. Also, it was shown that experimental defect ensembles differ when comparing different ensemble determination methods on the same sample. Results reveals that ablation caused contamination are the main factor limiting adequate comparison of both techniques. |
