Visible Discrimination of Broadband Infrared Light by Dye-Enhanced Upconversion in Lanthanide-Doped Nanocrystals

Figure 3

Upconversion spectra for Er³⁺-doped NaY_0.85Er_0.15F₄, in which the Er³⁺ ion acts as both sensitizer and activator. Excitation at 801 nm, 975 nm, and 1550 nm (black, blue and magenta curves, resp.) results in nearly identical emission spectra with a slight enhancement of the 655 nm emission for excitation at 1550 nm.