We present a simple modification of the tube etching process for the fabrication of fiber probes for near-field optical microscopy. It increases the taper angle of the probe by a factor of two. The novelty is that the fiber is immersed in hydrofluoric acid and chemically etched in an upside-down geometry. The tip formation occurs inside the micrometer tube cavity formed by the polymeric jacket. By applying this approach, called reverse tube etching, to multimode fibers with 200/250 mm core/cladding diameter, we have fabricated tapered regions featuring high surface smoothness and average cone angles of 301. A simple model based on the crucial role of the gravity in removing the etching products, explains the tip formation process.
Wide angle near-field optical probes by reverse tube etching
PATANE', Salvatore
;ARENA, Antonella;
2006-01-01
Abstract
We present a simple modification of the tube etching process for the fabrication of fiber probes for near-field optical microscopy. It increases the taper angle of the probe by a factor of two. The novelty is that the fiber is immersed in hydrofluoric acid and chemically etched in an upside-down geometry. The tip formation occurs inside the micrometer tube cavity formed by the polymeric jacket. By applying this approach, called reverse tube etching, to multimode fibers with 200/250 mm core/cladding diameter, we have fabricated tapered regions featuring high surface smoothness and average cone angles of 301. A simple model based on the crucial role of the gravity in removing the etching products, explains the tip formation process.Pubblicazioni consigliate
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