Micro-hole drilling in thin films with cw low power lasers

In this work, we perform drilling of micro-holes and micro-patterning in indium tin oxide (ITO) and titanium thin films. In ITO films the drilling is performed by thermocavitation only; meanwhile in titanium two competing processes are identified: (i) laser-induced sublimation producing high-quality micro-holes comparable to those produced with femtosecond pulses but at a reduced cost and (ii) erosion by thermocavitation which tend to degrade the quality of the micro-holes. The micro-holes can be employed as micrometer light sources for use in point-diffraction interferometers or spatial filters; in addition, micron-sized resolution patterning can be performed. (C) 2011 Optical Society of America