FOCUSING OF LASER-RADIATION IN THE NEAR-FIELD OF A TIP (FOLANT) FOR APPLICATIONS IN NANOSTRUCTURING

Current research work has shown that 'focusing' of laser radiation dow n to a few nanometres can be achieved by using near-field technology, e.g. scanning tunnelling microscopy (STM) or atomic force microscopy ( AFM), in combination with a laser. Lateral external illumination of a probe tip with laser radiation can cause a tremendous intensity enhanc ement of up to 5 x 10(5) in the near-field underneath the probe tip. T his effect can be explained by different electrostatic as well as elec trodynamic effects known from surface-enhanced raman spectroscopy (SER S). This enhancement effect was utilized to concentrate laser radiatio n with high intensity between a tip and a substrate. This FOLANT (focu sing of laser radiation in the near-field of a tip) technique can be a pplied for material processing on a nanometre scale. Using an STM/lase r combination, hillocks, pits and grooves with lateral dimensions down to 10 nm have been obtained on gold substrates. The AFM/laser combina tion enabled nanostructures down to 20 nm to be established on dielect ric materials such as polycarbonate. (C) 1997 by John Wiley & Sons, Lt d.