Optical Hollow Fiber for CO2 Laser Light Transmission Used in Endoscopic Therapy

Optical hollow fibers with inner dielectric and metal thin layers can deliver efficiently IR laser light which conventional silica fibers cannot be used for. A new novel endoscopic system using CO2 laser is being developed, in which such hollow fibers are considered as key devices. Compared to many other kinds of solid-core IR fibers, the hollow fibers have some advantages from the viewpoint of physical and chemical features as well as optical properties. CO2 laser light and visible aiming light transmitted through the hollow fiber are irradiated to tissues with a noncontact condition, in which the irradiating point can be grasped precisely. Unlike Nd:YAG lasers for endoscopic therapy as laser scalpels which were once widely evaluated, the light of CO2 laser does not penetrate deeply into the normal tissue and has an outstanding effect for cutting out appropriately a treatment area. The laser endoscopic system composed of the CO2 laser source and the hollow fiber is promising for a safer new method, especially a minimally invasive treatment for early stage of gastrointestinal cancers.