Production and Evaluation of a Holographic Lens

This thesis is concerned with the production of high diffraction efficiency holographic lenses for laser machining. A holographic lens is a high efficiency, low absorption phase hologram which, in this application, is used to diffract an expanded, highpower laser beam into a desired focal point or pattern. For ideal phase holograms, the coupled–wave theory, as applied by H. Kogelnik1, predicts diffraction efficiencies as high as 100%. This implies that all the power in the expanded laser beam could be diffracted into the focal point or pattern. Single focal point holographic lenses have been produced with 40% diffraction efficiency. These lenses were produced by reversal bleaching Kodak type 649F spectroscopic plates. 50% diffraction efficiency has been obtained with holographic lenses which have a focal pattern. These lenses were constructed on Agfa type 8E75 Scientia plates using a modified reversal bleach process