Up-conversion emission of Er3+ ions in Yb3+ sensitized oxide crystals

Most of the up-conversion lasers operated at room temperature are realized with heavy metal fluorides. In this paper the Judd-Ofelt parameters Omega(lambda)(lambda = 2,4,6) were calculated for Er3 + ions in Yb3 + sensitized LiNbO3 and YVO4 crystals at room temperature, together with the radiative transition probabilities, non-radiative transition probabilities and resonant transition probabilities of Er3 + ions. Taking into account the energy transfer from Yb3 + to Er3 +, the rate equations are given for Er3 + ions. We obtained from a solution of the rate equations that Yb3 + sensitized YVO4 crystal is more efficient than Yb3 + sensitized LiNbO3 crystal in the up-conversion of 550 nm of Er3 + emission, which is consistent with our observation.