THE TETRAHEDRAL TIP AS A PROBE FOR SCANNING NEAR-FIELD OPTICAL MICROSCOPY AT 30-NM RESOLUTION

The tetrahedral tip is introduced as a new type of a probe for scannin g near-field optical microscopy (SNOM). Probe fabrication, its integra tion into a scheme of an inverted photon scanning tunnelling microscop e and imaging at 30 nm resolution are shown. A purely optical signal i s used for feedback control of the distance of the scanning tip to the sample, thus avoiding a convolution of the SNOM image with other simu ltaneous imaging modes such as force microscopy. The advantages of thi s probe seem to be a very high efficiency and its potential for SNOM a t high lateral resolution below 30 nm.