Patent ID: 7099533

Claim:
A fiber optic infrared laser beam delivery system comprising the following components: (a) input coupling optics adapted to focus an infrared laser beam onto a predetermined focal spot; (b) a hollow core photonic band gap (HC-PBG) fiber made of non-silica-based glass and having an input end and an output end, said HC-PBG fiber being held by a holding fixture in a position such that its input end faces, the input coupling optics and its hollow core at the input end constitutes the predetermined focal spot onto which the infrared laser beam is focused; (c) a mask with an aperture having the same or slightly smaller diameter than that of the hollow core of the HC-PBG fiber, provided between the input coupling optics and the input end of the HC-PBG fiber, said mask being positioned so that its aperture is aligned with the hollow core and so that the infrared laser beam focused onto the hollow core first passes through the aperture of the mask and then enters the hollow core without touching any photonic band gap structure of the HC-PBG fiber that surrounds the hollow core at the input end; and (d) output coupling optics for the infrared laser beam emerging from the output end of the HC-PBG fiber.