Permanent luminescent micropatterns photoinduced by low-power ultraviolet irradiation in lithium fluoride

The permanent recording of regularly spaced, periodic, light-emitting submicrometric structures in gamma-ray irradiated LiF crystals has been obtained by low-power illumination with a continuous laser at 244nm in a standard phase mask interferometer used for Bragg gratings registration in optical fibers. Selective bleaching of primary F electronic defects and aggregate F2 laser active color centers has been identified as the mechanism responsible of photoinduced spatial modulation of absorption and photoemission properties. The results look promising for the realization of micropatterns with refractive index and gain modulation on scale comparable with the optical wavelengths to easily integrate with miniaturized LiF-based structures.

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