Infrared transmitting optical fibers and their medical applications

Infrared (IR) laser radiation, such as that of the CO₂ laser, is useful for cutting, heating, and welding. All of these methods and devices would be easily adapted for medical applications. In all of these, there is a need to transmit the IR radiation through suitable optical fibers. There are three families of IR transmitting fibers, namely: fibers made of IR glasses; fibers made of crystalline materials; and hollow waveguides. IR fibers made of crystalline silver halides in lengths of 0.7-1.0 mm are developed. These fibers are flexible, highly transparent in the middle IR, non-toxic, non-hygroscopic and biocompatible. They are used, in particular, for endoscopic laser surgery, therapy, diagnosis and imaging.