Mechanism for femtosecond laser pulse patterning of self-assembled monolayers on gold-coated substrates

Self-assembled monolayer (SAM) patterning on gold thin films was performed using 800 nm, 118 fs laser pulses. SAM removal was ablative and was observed at fluences near the multishot ablation threshold for the thin gold film. Line widths six times smaller than the 2 e-folding intensity beam diameter were observed demonstrating sub-diffraction limited patterning with femtosecond lasers. Similar experimental results in air and N2 indicated that the removal process does not involve oxidation of the gold-sulfur bond as was claimed in the literature