Sensor for converting a distance to optical and further to electrical energy, and surface scanning apparatus using same.

摘要

A sensor body (1) is formed as a light waveguide for laser light (2). A light exit site (10) for light diffracted within the sensor body (1) is located at a surface (6) thereof which faces away from a measured body (M). A detection particle (15) is located at the surface (5) of the sensor body (1) facing the measured body (M). It has a substantially convex and rounded off form and a major dimension which is smaller than the wavelength of the light (2). The measured body (M) is located in the optical near field of the detection particle (15). The latter has a major dimension of 5 to 500 nm and preferably of 20 to 100 nm. A detector means (11) converts the optical energy of the diffracted light to an electrical detector signal. A continuous thin film (16) is provided as a coating for the sensor (S). It substantially covers the detection particle (15) and at least part of the surface (5) of the sensor body (1) in the vicinity of the detection particle (15) It has a thickness which is smaller than one half of said predetermined wavelength. Preferably it is formed of gold and has a thickness of less than 100 nm. The sensor is used to finally convert a distance to an electrical quantity.