Mechanism of the Yb–Er energy transfer in fluorozirconate glass

Abstract

The mechanism of the Yb 3ϩ →Er 3ϩ energy transfer as a function of the donor and the acceptor concentration was investigated in Yb 3ϩ -Er 3ϩ codoped fluorozirconate glass. The luminescence decay curves were measured and analyzed by monitoring the Er 3ϩ ( 4 I 11/2 ) fluorescence induced by the Yb 3ϩ ( 2 F 5/2 ) excitation. The energy transfer microparameters were determined and used to estimate the Yb-Er transfer rate of an energy transfer process assisted by excitation migration among donors state ͑diffusion model͒. The experimental transfer rates were determined from the best fitting of the acceptor luminescence decay obtained using a theoretical approach analog to that one used in the Inokuti-Hirayama model for the donor luminescence decay. The obtained values of transfer parameter gamma ͓␥͑exp͔͒ were always higher than that predicted by the Inokuti-Hirayama model. Also, the experimental transfer rate, ␥ 2 (exp), was observed to be higher than the transfer rate predicted by the migration model. Assuming a random distribution among excited donors at the initial time (tϭ0) and that a fast excitation migration, which occurs in a very short time (t Ӷ␥ Ϫ2 ), reducing the mean distance between donor ͑excited͒ and acceptor, all the observed results could be explained.

Dynamics of Tm–Ho energy transfer and deactivation of the F43 low level of thulium in fluorozirconate glasses

“…In this case, ET1 efficiency exhibits a similar Tm concentration dependence as was observed for the case of Tm→Ho ET, however with a slight increase of the fast excitation diffusion critical radius (R C ϭ14.5 Å). Based on our previous report, 8 it was demonstrated again, in the present work, that the method of analyzing the time dependence of the luminescence from the acceptor viewpoint is an important tool to investigate the mechanism of the energy transfer among rare-earth ions in solids.…”

“…11 Based on this observation, we concluded that the Tm-Ho ET and Tm-Tm CR are a fast-excitation diffusiondependent energy transfer mechanism similar to the one observed for the Yb→Er energy transfer in ZBLAN glass. 8 As a consequence, the hypothesis on the occurrence of fast excitation diffusion occurrence before the direct D* -A resonant energy transfer is reinforced.…”

“…We have already shown that the Inokuti-Hirayama solution from the acceptor viewpoint is an important tool to investigate the mechanism of resonant energy transfer among tripleionized rare-earth ions in glasses. 8 An expression in which the Inokuti-Hirayama approach is used together with the proposed localized donor-to-acceptor interaction ͓dipole-dipole (sϭ6)] solution has been used in the determination of experimental transfer rates and efficiencies for Tm-Ho, Tm-Tm cross relaxation and Tm-Tm migration. The temporal dynamics of the excited levels of Tm 3ϩ and Ho 3ϩ ions were measured using a pulsed laser excitation ͑4 ns͒ from a tunable optical parametric oscillator ͑OPO͒ pumped by the second harmonic of a Q-switched Nd-YAG laser which can pump exactly the level to be investigated.…”

Ultra-low-threshold Er:Yb sol-gel microlaser on silicon

“…For example, previous research has investigated fabricating erbium and ytterbium doped microtoroid resonant cavity-based lasers using either ion implantation or sol-gel techniques [26][27][28]. While these detailed studies did successfully demonstrate single ion doped toroid microlasers, it is well-known that co-doped lasers have significantly improved performance over single doped devices, because the absorption efficiency of the primary dopant is increased by the secondary dopant (sensitizer) [29,30]. The Er…”

Low threshold Er3+/Yb3+co-doped microcavity laser

“…Previous research has investigated fabricating single ion doped toroid microlasers, ie erbium and ytterbium doped microtoroid resonant cavity lasers using either sol-gel techniques or ion implantation [25][26][27]. However, it is well-known that co-doped lasers have significantly improved performance over single doped devices, because the secondary dopant (sensitizer) can increase the absorption efficiency of the primary dopant [28,29]. In this work, an ultra-low threshold co-doped microlaser is made by combining the large optical cross section of Er 3+ :Yb 3+ co-doped sol-gel and with the high circulating intensities present in ultra-high-Q optical microcavities.…”