Surgical laser beam transmitter with short focus lens - directs pulsed optical energy at restricted portion of end of coated fibre placed beyond focal distance

摘要

The parallel beam (2) from a solid (e.g. Er:YAG) laser (1) is brought by the lens (3) to a focus (4) ahead of the entry face (5) of the core (7) of a thinly coated optical fibre (6). The angle (10) within which the focused beam falls on less than 75 percent of the face (5) is chosen equal to or slightly less than the numerical aperture angle. This guarantees total reflection at the interface (9) between the fibre core (7) and its coating (8). USE/ADVANTAGE - Esp. in middle infrared wavelength range around 2.94 microns, coupling into fibre is achieved with min. loss.