Luminescence in various classes of Er3+-doped inorganic compounds under IR excitation

We have studied the luminescence of various classes of Er 3+ -doped inorganic phosphors under IR excitation. The highest IR Stokes luminescence efficiency in the range 1.5–1.6 μm is offered by Yb 0.99 Er 0.01 PO 4 (xenotime structure). This efficient IR phosphor has been commercialized under the name AM-1500M-1. It is of considerable practical interest for security and authentication applications and also as a gain medium for mid-IR lasers operating in the spectral range 1.5–1.6 μm, safe to the human eye.