Optical fibre probe for optical near field microscope

摘要

The probe has a tip which scans the surface of the sample to be microscoped in a raster manner. The probe tip is guided at a distance from the sample surface. The distance is small relative to the optical wavelength used. The probe has a connector (10) for coupling in the measurement light. A photo-refractive Bragg grating (2) is arranged along the fibre axis in tapering parts of the optical probe (1). Couplers (4,5) are provided on the monomode optical waveguide (11) for coupling detection light in and out of the waveguide for scan detection. The couplers couple in and out the detection light so that the change in optical reflection behaviour of the Bragg grating caused when the probe tip approaches the sample surface is used to control the distance between the tip and the sample surface.