Thickness-dependent laser photothermal effects in rare-earth metal-oxide films for contamination control

The growing adoption of atomic absorption spectroscopy has raised concerns about laser-induced contamination degradation of optical components. While previous research has predominantly focused on carbon-based pollutants, this study pioneered the investigation of rare-earth metal oxides, uncovering a thickness-dependent photothermal response in neodymium oxide-contaminated layers under 10 kHz repetition-rate laser irradiation. Through combined experimental and computational analyses, we established a predictive model demonstrating a linear relationship between the surface temperature and the linear dependence of surface temperature fields on both laser power (20-100 W) and absorption rate, with a model prediction accuracy exceeding 99.3%. In addition, beam-diameter modulation was shown to mitigate the thermal effects nonlinearly. These insights culminate in a thickness-absorption rate phase diagram for rare-earth metal-oxide contamination, providing a quantitative threshold criterion for real-time contamination monitoring. Furthermore, the proposed laser power absorption rate phase diagram offers actionable strategies for mitigating thermal distortions in high-power laser systems.