Abstract

A class of fiber tip radiating laser light mainly along a cone coaxial to the fiber has been extensively studied in the past few years, and tests have been carried out, for example, in gastroentherology to remove occluding cancers. Their interest in treating obstructions in blood vessels or bronchos is also well known. In practice, however, these fiber tips consisting of cones or truncated cones are not safe in medical applications, in particular, in endoscopy. The cones indeed still radiate a non-negligible part of the light on-axis, particularly in the case of truncated cones. In these cases, the wall of vessels or other cavities can be damaged. Moreover, the conical tips can easily break. Recently more sturdy sapphire tips have become available, but their size frequently does not fit the vessel lumen while the high refractive index results In a different optical behavior with respect to quartz cone tips.

© 1988 Optical Society of America