Method to produce high-resolution scanning near-field optical microscope probes by beveling optical fibers

A new two-step method to fabricate scanning near-field optical microscope ( SNOM) probes with an aperture size clearly below 100 nm has been developed. For the first step, a chemical etching process is used in which an optical fiber is dipped with its acrylate jacket into hydrofluoric acid to get a s uitable tapered shape of the fiber. The second step consists of beveling th e etched fiber using a modified micropipette beveler to obtain a tip diamet er in the nanometer range as well as a smooth surface to allow a good alumi num metallization by evaporation. By varying the beveling angle tapered sha pes with different cone angles can be obtained. First transmission experime nts with our probes show an optical resolution below 80 nm. In comparison t o fiber tips obtained by a standard heating and pulling method, the transmi ssion efficiency of these tips is up to three orders of magnitude higher du e to the optimized tapered shape. (C) 2000 American Institute of Physics. [ S0034- 6748(00)01208-9].