| 摘要 |
A medical laser delivery device having lensed caps at the fiber's distal end and capable for sideways directed radiation can produce high power densities at a distance further away from the fiber, and thus enable non-contact ablating procedures to be carried out with lower laser input power levels. An innovative manufacturing method to accomplish this goal is described as well as a novel design and method to affix caps to the optical fibers in a permanent manner unaffected by thermal heating of the device in operation. Also Fresnel reflections can be reduced by some embodiments of the lensed caps. The improvements can be achieved in several ways: including shaping part of a transparent quartz glass cap into a lens in the main exit direction of the beam; using highly refractive optical materials, such as transparent sapphire, as the cap, and shaping a portion thereof into a lens in the main exit direction; or, more generally, using caps made of any medically suitable material and inserting a microlens in the exit path of the beam. The glass cap can be fused with the fiber at the point of the main beam exit thus effectively reducing Fresnel losses. The glass cap can be further fused with the fiber around the entire circumference to permanently seal it onto the fiber tip. This fusion is possible by utilizing a new innovative laser heating and fusing mechanism. When this fusion is performed, before the lens is formed, in the region of the beam path (sideways directed), the formation of a focusing lens is greatly simplified. <MATH> |
