Patent ID: 7498564

Claim:
A scanning near-field optical microscope comprising: a probe which is moveable into a near-field region surrounding a surface of an illuminated sample; driving means arranged to provide relative motion between the probe and the sample surface; means for oscillating the probe laterally across the surface; and a detector arranged to detect electromagnetic radiation affected by an interaction between the probe, an electromagnetic field, and the sample in the near-field region; the microscope is arranged, in operation, to carry out a scan of the sample surface wherein scan area is covered by an arrangement of scan lines, each scan line including a plurality of pixels and being collected by oscillating the probe laterally at or near its resonant frequency such that an oscillation amplitude corresponds to a scan line length and the arrangement of scan lines is provided by operation of the driving means; the relative motion between the probe and the sample surface is provided at an adjustable separation distance, this distance during the scan being controlled by height-adjustment means arranged to monitor a parameter characteristic of probe-surface distance and to adjust either probe or sample height in order to maintain a substantially constant value of that parameter; and the electromagnetic field is a substantially evanescent field and the parameter characteristic of probe-surface distance is a photon current.