Cooperative downconversion in Yb~(3+)-RE~(3+) (RE(velence)Tm or Pr) codoped lanthanum borogermanate glasses

摘要

We report on cooperative downconversion in Yb~(3+)-RE~(3+) (RE(velence)Tm or Pr) codoped lanthanum borogermanate glasses (LBG), which are capable of splitting a visible photon absorbed by Tm~(3+) or Pr~(3+) ions into two near-infrared photons. The results indicate that Pr~(3+)-Yb~(3+) is a more efficient ion couple than Tm~(3+)-Yb~(3+) in terms of cooperative downconversion. We have obtained a highest quantum yield of 165percent and 138percent for Pr~(3+)-Yb~(3+) and Tm~(3+)-Yb~(3+) codoped LBG glasses under 468 nm excitation, respectively. However, ultraviolet light excitation to the charge transfer band of Yb~(3+) does not result in quantum splitting as rapid relaxation from the charge transfer band to 4f~(13) levels of Yb~(3+) dominates.