Hoven, van den, G.N.; Snoeks, E.; Polman, A.; Dam, van, C.; Uffelen, van, J.W.M.; Smit, M.K.
Published in:Journal of Applied Physics Published: 01/01/1996
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Citation for published version (APA):Hoven, van den, G. N., Snoeks, E., Polman, A., Dam, van, C., Uffelen, van, J. W. M., & Smit, M. K. (1996). Upconversion in Er-implanted Al2O3 waveguides. Journal of Applied Physics, 79(3), 1258-1266.
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Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. When pumped with a 1.48 m laser diode, Er-implanted Al 2 O 3 ridge waveguides emit a broad spectrum consisting of several distinct peaks having wavelengths ranging from the midinfrared ͑1.53 m͒ to the visible ͑520 nm͒. In order to explain these observations, three different upconversion mechanisms are considered: cooperative upconversion, excited state absorption, and pair-induced quenching. It is found that for samples with a high Er concentration ͑1.4 at. %͒, cooperative upconversion completely dominates the deexcitation of the Er 3ϩ ions. For a much lower concentration ͑0.12 at. %͒, the influence of cooperative upconversion is strongly reduced, and another upconversion effect becomes apparent: excited state absorption. These conclusions are based on measurements of the luminescence emission versus pump intensity, and also on measured luminescence decay curves. The upconversion coefficient is found to be ͑4Ϯ1͒ϫ10 Ϫ18 cm 3 /s; the excited state absorption cross section is ͑0.9Ϯ0.3͒ϫ10 Ϫ21 cm 2 . It is shown that in spite of these upconversion effects, a high fraction of the Er 3ϩ can be excite...
