Direct production of gratings on plastic substrates using 248-nm KrF laser radiation

A technique is described for the direct production of holographic diffraction gratings on polyethylene terephthalate and polyimide films by irradiation with interfering KrF laser beams. Surface relief type gratings with spatial frequencies of 630-2900 lines/mm have been produced and characterized as to their diffraction efficiency in both transmission and reflection modes. The resultant measurements are discussed in terms of predicted diffraction efficiencies and formation mechanisms involving ablation of the surface layer.