Menu
Cart

Scientists at Lawrence Livermore National Laboratory reported progress in upconversion-pumped luminescence efficiency with rare earth doping

Posted by MSE Supplies on

Upconversion-pumped luminescence efficiency of rare-earth-doped hosts sensitized with trivalent ytterbium

Ralph H. Page,1 Kathleen I. Schaffers,1 Phillip A. Waide,1 John B. Tassano,1 Stephen A. Payne,1William F. Krupke,1 and William K. Bischel2

1Lawrence Livermore National Laboratory, University of California, P.O. Box 808, Mailcode L-441, Livermore, California 94550 USA

2Gemfire Corporation, 2440 Embarcadero Way, Palo Alto, California 94303 USA

Order high purity rare earth metals and compounds from msesupplies.com

Abstract

We discuss the upconversion luminescence efficiencies of phosphors that generate red, green, and blue light. The phosphors studied are single crystals and powders codoped with Er3+ and Yb3+ and with Tm3+ and Yb3+. The Yb ions are pumped near 980 nm; transfers of two or three quanta to the codoped rare-earth ion generate visible luminescence. The main contribution is the quantitative measurement of this upconversion efficiency, based on the use of a calibrated integrating sphere, determination of the fraction of pump light absorbed, and careful control of the pump-laser-beam profile. The green phosphors are the most efficient, yielding efficiency values as high as 4%, with the red and blue materials giving 1%–2%. Saturation was observed in all cases, suggesting that populations of upconversion steps of the ions are maximized at higher power. Quasi-cw modeling of the intensity-dependent upconversion efficiency was attempted; input data included level lifetimes, transition cross sections, and cross-relaxation-rate coefficients. The saturation of the Yb,Er:fluoride media is explained by the pumping of Er3+ ions into a bottleneck (long-lived state), that is, the 4I13/2metastable level, making them unavailable for further excitation transfer.

 Order high purity rare earth metals and compounds from msesupplies.com

© 1998 Optical Society of America

https://www.osapublishing.org/josab/abstract.cfm?URI=josab-15-3-996

Related Posts


Share this post



← Older Post Newer Post →


Leave a comment

Please note, comments must be approved before they are published.