Y2O3 : Yb : Er‐New Red‐Emitting Infrared‐Excited Phosphor

Y2O3 : Yb : Er and Gd2O3 : Yb : Er are efficient phosphors that emit red light when excited by the absorption of ir radiation. A number of processes are important in suppressing the green emission normally seen in erbium‐ytterbium double‐doped phosphors, and in emphasizing the often weak red emission. These processes are discussed in detail. An over‐all electrical‐to‐light power conversion efficiency of (3–5) × 10−4 was observed, from which an internal ir‐to‐visible conversion efficiency of 30–55% was inferred. It is concluded that, regardless of coupling efficiency, GaAs : Si ir generation efficiencies and inherently broad incoherent infrared diode emission spectra will limit over‐all efficiencies in diode‐excited phosphors to about 1%.