Laser patterning of thin films for luminescence applications

Fresnoite, Ba₂TiSi₂O₈, possesses a very intense and broad photoluminescence band similar to that of the most intense oxide scintillator materials. As such, fresnoite is to be considered a well-suited material for photonics applications, including phosphors. Complete miscibility with the isotypic fresnoite compounds Ba₂TiGe₂O₈ and Sr₂TiSi₂O₈ as well as doping with rare-earth ions facilitates colour-space design. In order to qualify fresnoite as a material for photonic applications, fresnoite thin films were synthesized on a-plane sapphire, upon which, in comparison to growth on silicon (100), quartz, and MgO (100), the texture is most pronounced. Infrared-laser direct writing in amorphous fresnoitic films on sapphire allows a spatially resolved crystallization and an enhancement of the luminescence intensity by about three orders of magnitude. The latter fact can be utilized for UV-sensitive marking and wavelength converters.