DELIVERY OF RADIATION FROM A FIRST TRANSPARENT MEDIUM TO A SWCOND TRANSPARENT MEDIUM HAVING A LOWER REFRACTION INDEX

摘要

A method of delivering guided radiation arriving via a first transparent medium having a first refraction index n1, into a second transparent medium having a second refraction index n2 that is smaller than n1, comprising providing a transparent radiation delivery waveguide (3) having a longitudinal axis and a third refraction index n3 substantially equal to or greater than n1 and adapted to guide said radiation along said longitudinal axis, said waveguide having a tapered radiation delivery portion (5) of non-circular cross- sectional shape, mounting said waveguide in optical contact with said first transparent medium and so that said radiation delivery portion projects inside said second transparent medium, and causing said first transparent medium to take up radiation whereby radiation transmitted by the waveguide is extracted through the radiation delivery portion into said second transparent medium.