Two- and three-photon upconversion of LaOBr:Er3+

In this work, the LaOBr:Er3+ (0.1%) powders were prepared by solid state reaction. The structural properties of LaOBr:Er3+ were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results show that LaOBr:Er3+ has low phonon energy, which indicate that LaOBr:Er3+ may have high luminescent efficiency. Under excitation into 4I11/2 level of Er3+ ions by 980 nm laser, the two- and three-photon upconverted luminescence of LaOBr:Er3+ were recorded. The most intense emissions were come from the 2H11/2, 4S3/2 → 4I15/2 transitions. The upconversion mechanisms were studied in detail through laser power dependence, and results show that excited state absorption is responsible for the upconversion. The upconversion properties indicate that LaOBr:Er3+ may be used in upconversion phosphors.