Microstructure formation on titanium oxide (TiO₂) coatings by femtosecond laser irradiation

Abstract

Depressions were generated on a titanium oxide coating of 100 nm thickness by irradiation with a femtosecond laser with a pulse width of 100 fs when the laser output was below 10 mW. When the number of pulses was five or less, irregularities were found to be generated on the coating surface in the area corresponding to the periphery of the pulses, where the laser intensity is low, while titanium oxide was removed from the area corresponding to the center of the pulses. The formation of microstructures is expected on the surface of titanium oxide coatings by setting the output of a femtosecond laser in the periphery of the pulses to below a certain value.