| Popis: |
The new material processing characteristic of aluminum nitride (AlN) ceramic is compared with microsecond, nanosecond and femtosecond laser ablation. The conventional laser material processing technology with longer pulsewidth laser such as TEA CO2 laser, Q-switched YAG laser, and excimer lasers leads to the thermal shock or lateral damage on target material, and those thermal effect causes the surface modification of AlN ceramic target. The comparative study of the laser ablation with microsecond TEA CO2 laser pulse, nanosecond KrF excimer laser pulse, and femtosecond Ti:sapphire laser pulse is performed in time domain. Using intense ultrashort titanium sapphire laser two-photon laser ablation of TiO2 photo-catalyst was also investigated experimentally and theoretically aiming at the enhancement of photo-catalyst reaction. The black-surfacing of the TiO2 photo- catalyst crystal was successfully achieved by drilling a large number of conical micro-holes with two-photon laser ablation. The ablated surface has a roughness of sub micrometer order, and no heat-affected zone was observed. The simple equation is developed to explain two-photon ablation process of the TiO2 photo- catalyst and the dependence of the ablation characteristic on the pulsewidth.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
