Room-temperature green upconversion fluorescence of an Er3+-doped POCl3—SnCl4 solution is achieved when the solution is pumped with an 800-nm GaAs laser diode. The upconversion emission at 550 nm is determined to be the result of a two-step absorption process. Numerical analysis reveals that laser systems that employ this erbium-doped laser liquid should be realizable with threshold pump powers as low as 45 mW.
© 1996 Optical Society of America
C. Koeppen, G. Jiang, G. Zheng, and A. F. Garito, "Room-temperature green upconversion fluorescence of an Er3+-doped laser liquid," Opt. Lett. 21, 653-655 (1996)