Nanofabrication induced by near-field exposure from a nanosecond laser pulse

We demonstrate a photoinduced nanofabrication method, applicable to dimensi ons beyond the diffraction limit, by employing a nanosecond laser pulse wit h a high peak power. The second-harmonic wave of a Nd: yttrium-aluminum-gar net (YAG) laser with a 5 ns pulse width was irradiated onto the sample, whi ch consisted of a hexagonal arrayed monolayer of nanoparticles on an azopol ymer film. Topographical changes in the surface after irradiation were obse rved by atomic force microscopy. A transcription of the arrayed structure i n the form of a dent structure was attained. In the case of 100 nm nanopart icles, the resolution of the transcription was beyond the diffraction limit . The dent depth and diameter were changed depending on the diameter of the nanoparticles and the irradiation power used. A depth analysis indicates a threshold for the ablation process. (C) 2001 American Institute of Physics .