TECHNICAL DESCRIPTION

The invention relates to a nanoprobe comprising a silica fibre with an end opening having a diameter of less than 100 nm, and a metallic sheath. More precisely, the method involves immersing an end comprising a silica optical fiber in a chemical medium intended for an etching process for obtaining a silica cone. A non-adherent sheath in the form of an opaque conducting film is deposited on the cone by plasma spray and by placing the optical fiber on an axis of a hollow cylindrical cathode. An opening is formed at the end of the cone by point-plane filamentary discharge between the end and a plane surface.