Ultrabroadband near-infrared luminescence and efficient energy transfer in Bi and Bi/Ho co-doped thin films

Ultrabroadband near-infrared luminescence in the 1.0-2.4 mu m range has been observed in bismuth (Bi)-doped oxyfluoride germanate thin films prepared by pulsed laser deposition (PLD). The emission peak position shows a red-shift with decreasing oxygen pressure during PLD growth. Systematic investigation reveals that the origin of the luminescence could be ascribed to Bi clusters. With the sensitization of Bi near-infrared active centers, enhanced broadband similar to 2 mu m luminescence of Ho super(3+) is realized in Bi/Ho co-doped films, and a high energy transfer efficiency is obtained. These results may provide promise to realize planar waveguide lasers in the near-infrared region for integrated optics.