The ablation of Ta2O5 film by pulsed nanosecond Gaussian laser beams

Ta2O5 thin film has many advantages: wide spectral range, high refractive index and so forth, which endow Ta2O5 with great potentials in high power laser systems. Based on experimental observations and thermodynamic process analysis, the Ta2O5 thin film damage by Gaussian beam of nanosecond pulses was investigated. For the Gaussian beam, laser pulse energy is concentrated at the center of the laser beam, which determines the ablation characters. The material removal is deepest at the center and gradually decreases along radial direction, rendering the removal profile funnel-shaped. The ablation microstructures are characterized by resultant nano-particles owing to ablation in the concave–convex structures. The nano-particles spread gradually from the center throughout the ablation region. This variation is mainly due to the transition of the film damage from melting into atomization and ultra-high temperature melting and cooling.