Femtosecond laser ablation of TiO/sub 2/ photocatalyst by multiphoton absorption

We process a flat TiO/sub 2/ crystal surface by femtosecond pulse laser ablation. We create micro-holes densely on the flat surface to increase the surface area. The dense holes increase the surface area and also decrease the light reflection because the light reflects many times in the conical hole, and so the photocatalysis effect is greatly accelerated by these two effects. Femtosecond laser ablation reduces collateral (thermal and mechanical) damage of ablation and increases the reproducibility. The TiO/sub 2/ ablation is due to a multiphoton absorption process.