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A novel etching method for an optical fibre probe of a scanning near-field optical microscope (SNOM) was developed to fabricate a variety of tip shapes through dynamic movement during etching. By moving the fibre in two-phase fluids of HF solution and organic solvent, the taper length and angle can be varied according to the movement of the position of the meniscus on the optical fibre. This method produces both long (sharp angle) and short (wide angle) tapered tips compared to tips made with stationary etching processes. A bent-type probe for a SNOM/AFM was fabricated by applying this technique and its throughput efficiency was examined. A wide-angle probe with a 50 degrees angle at the tip showed a throughput efficiency of 3.3 x 10(-4) at a resolution of 100 nm.

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SummaryWe have developed a high-speed scanning near-®eld optical microscope (SNOM)/atomic force microscope (AFM) system including dual feedback controllers. The system includes an additional piezoelectric actuator with fast response in the z direction and a correction circuit to eliminate unnecessary components from the feedback signal. From the measurement of a patterned chromium layer of 2´2 mm 2 checks on a quartz glass plate, we con®rmed that our system had more effective feedback control and faster scanning than current SNOM/AFM systems that use only a piezo-tube. The scanning speed of the present system was estimated to be about ®ve times faster than that of current SNOM/AFM systems.

We report on the development of a prototype system for the automatic characterization of the pit shape in optical master disks (OMDS) and its relationship with the corresponding optical readout signal. The system consists of two basic components: an optical disk drive tester (ODDT) which uses a laser beam pickup to convert physical pits on the master disk into electrical signals and an integrated atomic force microscope (AFM). In this system, the ODDT scans the OMD and records the positions of errors. Using these recorded positions, the integrated tapping-mode AFM unit then automatically positions the AFM head to the corresponding locations on the OMD and initiates a scan which serves to record topographical information of pit shape in the error regions. In an initial trial, the system was used to automatically detect and record topographical information on randomly written error patterns (1μm in length) recorded on a 12 cm diam optical disk. For each identified region, 50μm square AFM scans were then automatically recorded. The system thus allows the direct observation of the correlation between errors detected in the optical readout signal and the topology of the corresponding pit on the nanometer scale. As high reliability of the AFM unit is a prerequisite for automatic operation, a carbon nanotube based probe was developed and proved to be much more reliable than conventional Si based cantilevers.