Laser ablation of metals and ceramics in picosecond–nanosecond pulsewidth in the presence of different ambient atmospheres

Ablation tests of AlN, Si3N4, SiC, Al2O3 ceramics, steel and aluminum have been carried out in vacuum, air and argon atmospheres using UV (270 nm), visible (539 nm) and IR (1078 nm) picosecond (100÷150 ps) and nanosecond (6÷9 ns) laser pulses. Ablation rate dependencies have been measured in the range of laser energy densities varied from (2÷5)×101 J/cm2 to (5÷10)×103 J/cm2. Peculiarities of laser ablation processes at different wavelengths, pulsewidths and ambient gases are discussed. In particular, the efficiencies of laser ablation in picosecond and nanosecond regions are compared. The scanning electron microscope (SEM) pictures of high quality microstructures, deep and narrow cuts and holes produced in ceramics with typical size of tens microns and aspect ratio as high as 20, are demonstrated.