Optical absorption characteristics in thermally reduced Er : LiNbO 3 crystals

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)453-460
Journal / PublicationOptical Materials
Volume28
Issue number4
Publication statusPublished - Mar 2006

Abstract

Influence of thermal reduction on intrinsic (bipolarons), extrinsic (Er3+) defects and OH- groups in Er:LiNbO3 crystals, which were as-grown and VTE-treated (VTE: vapor transport equilibration) before being reduced, was studied by measuring the polarised or unpolarised optical absorption in visible and near infrared regions. A wide and strong band extending from the optical absorption edge up to the infrared region and peaking around 500 nm (∼2.5 eV), resulting from the absorption of reduction-induced bipolarons, is observed. Meanwhile, the thermal reduction also induces an additional, relatively much narrow absorption band around 370 nm in a crystal whether it is Er-doped or undoped and whether it is congruent or originally VTE-treated. Both the 500 nm and the 370 nm bands show similar polarisation dependence. The thermal reduction treatment hardly influences Er3+ spectroscopic properties such as absorption amplitude, linewidth, peaking position and polarisation dependence. The original VTE effects on the spectroscopic properties of Er:LiNbO3 crystal are essentially retained still. The thermal reduction has a similar effect on the OH- absorption to a strong VTE treatment: the removal of the OH - groups contained in the crystal. © 2005 Elsevier B.V. All rights reserved.

Research Area(s)

  • Bipolaron, Er:LiNbO3, OH - absorption, Optical absorption, Thermal reduction

Citation Format(s)

Optical absorption characteristics in thermally reduced Er: LiNbO 3 crystals. / Zhang, De-Long; Ma, Rui; Pun, E. Y B.
In: Optical Materials, Vol. 28, No. 4, 03.2006, p. 453-460.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review