Energy transfer upconversion in LaF3:Pr3+

Abstract

Studies of infrared quantum counter upconversion in LaF₃:Pr³⁺ and LaCl₃:Pr³⁺ have led to the discovery of a process in which a red excitation photon results in the emission of a blue photon. When the ¹D₂ level of Pr³⁺ is excited by a cw rhodamine 6‐G dye laser, blue fluorescence from the ³P₀ level is observed. From the flux dependence and lifetime of the induced fluorescence, we conclude that the observed phenomenon arises from excitation annihilation involving pairs of ions in the ³H₆ and the ¹D₂ states.