Patent ID: 8051493
Filing Date: 2011-11-01
Classification: B82Y,G01Q

Abstract:
1. A method of determining the position of a tip of a probe comprising: generating an evanescent electromagnetic field extending beyond an interface boundary between a first medium, having a first refractive index, and a second medium, having a second refractive index which is greater than the first refractive index, the interface boundary extending in a plane; positioning a probe tip in the evanescent field in the first medium thereby causing propagating electromagnetic radiation to be produced as a result of the disruption of the evanescent field by the probe tip; and collecting at least a portion of the propagating electromagnetic radiation, detecting the spatial intensity distribution of the collected radiation with respect to an image plane; and determining from the detected spatial intensity distribution an at least one dimensional position of the probe tip in a probe tip plane, the probe tip plane being a plane which contains the probe tip and which is substantially parallel to the plane of the interface boundary, wherein the position of the probe tip is determined as the probe bends along its length and the probe tip moves in the probe tip plane.