Infrared-to-visible Eu3+ energy upconversion due to cooperative energy transfer from an Yb3+ ion pair in a sol-gel processed multi-component silica glass

Energy upconversion of Eu3+ is demonstrated in a sol-gel processed silica glass co-doped with Yb3+ ions. Yellow-range emission is observed originating from the Eu3+ ions due to nonresonant cooperative energy transfer from pairs of excited Yb3+ ions when a diode laser emitting at a wavelength of 973 nm is used as an excitation source. The Yb3+-Eu3+ energy transfer rate is estimated as similar to 280 s(-1) based on an analysis of the Yb3+ infrared luminescence decay time. (C) 2000 Elsevier Science B.V. All rights reserved.