Fabrication of a high-transmission fiber probe for near-field scanning optical microscope

It is presented a one-step technique of fabricating a high-transmission fiber probe for near- field scanning optical microscope (NSOM). A commercial single-mode silica fiber with a low GeO2-doped core is etched in buffered hydrofluoric acid (HF). At a proper ratio of the etching solution, the tradeoff between tip cone angle and diameter is satisfied very well. Therefore, a selective chemical etching for special high doped fiber or a hybrid pull-etch process is not necessary. After coating tip with aluminum, we obtained fiber probes with typical parameters as follows : tip diameter of l00nm and transmission efficiency of 5. 5×10^-4.