Nd3+→ Cr4+ energy transfer in co-doped Nd,Cr:Y3Al5O12 garnet transparent ceramics

Abstract

Herein, we quantitatively analyze the Nd3+ → Cr4+ energy transfer efficiency in the co-doped transparent ceramic YAG host and determine that it can be maintained at less than a 20 % loss of Nd3+ excited states when the Cr4+ absorption coefficient at 1064 nm is less than 1.0 cm−1. Furthermore, we conclude that the energy transfer mechanism can be fully accounted for on the basis of classic Förster-Dexter theory, as the transfer efficiency deduced from the emission kinetics is consistent with that independently determined from the spectroscopic properties of Cr4+ absorption and Nd3+ emission. Systematic studies of trends for Cr3+ → Cr4+ conversion are reported as a function of the oxygen annealing temperature, initial Cr3+ concentration, and incorporation of divalent (Mg2+ and Ca2+) charge compensators. Lastly, no effect of energy migration among the Nd3+ ions was observed.

Keywords

• Transparent ceramic
• Optical ceramic
• YAG
• Energy transfer
• Cr4+
• Nd3+