Characteristics of Nanopatterns and the Associated Thermal Mechanisms During Near Field Laser-Material Interaction of Nanosecond Laser on Different Targets

Abstract

Nano-patterns are generated on semiconducting and metallic surfaces through coupling an apertured near field scanning optical microscope (NSOM) with a pulsed laser source in this study. To understand the dominant mechanisms for the generation of the nano-patterns, a series of experimental measurement of the size and shape of nano-patterns generated on targets under different experimental conditions with different targets is conducted. The characteristic dimensions of nano-patterns show dependence on optical properties of the target material. The qualitative trend of the variation of nano-patterns as a function of laser and material conditions indicates that the dominant mechanisms for the generation of nano-patterns through a combination of nanosecond laser and an apertured NSOM under different conditions studied is near field laser-material interaction.

Analysis of nanopatterning through near field effects with femtosecond and nanosecond lasers on semiconducting and metallic targets

“…Three main mechanisms 19 can be induced on the targets after absorbing energy from NSOM probes and are responsible for the nanopattern generation in this study. These three mechanisms are: ͑a͒ nanoscale laser ablation of the target, ͑b͒ nanoscale oxidation resulting form nanoscale heating of the target, and ͑c͒ nanoscale recrystallization resulting from nanoscale melting of the target.…”

“…However, based on the author's previous experiments, NSOM based nanoscale laser-material interaction is very sensitive to ͑a͒ material composition of the targets and ͑b͒ optical conditions of incident light. [17][18][19] Very tiny or even no nanopatterns can be generated on the targets unless well controlled experimental conditions are maintained. Also, the size and shape ͑e.g., protrusions and craters͒ of nanopatterns change significantly in different experimental conditions.…”