Apparatus for delivering a laser beam

Abstract

A beam delivery apparatus, including a set of focusing mirrors (or transmissive lenses) mounted along an endoscope channel. A laser beam can be focused into an input end of the channel with a smaller F number (wider cone angle) than is possible in a conventional endoscope. As the beam propagates down the channel, it is reflected (or transmitted) a finite number of times by the focusing elements. The focusing elements act as a periscope to focus and refocus the beam as it propagates along the channel, with little loss of beam power. The invention enables delivery of the beam to the channel's distal end with a smaller F number than can be achieved using a conventional endoscope. In a preferred embodiment, a pair of reflecting strips are mounted the channel, the surface of each strip defines six focusing mirrors, and the beam undergoes a total of twelve reflections from the mirrors as it propagates down the channel. Preferably, the surface of each mirror has a curvature selected to prevent the introduction of astigmatic distortion during each beam reflection.

Dependencies are inferred from the claim text.