%0 Journal Article
%T Judd-Ofelt Calculations for Nd3+-Doped Fluorozirconate-Based Glasses and Glass Ceramics
%A U. Skrzypczak
%A C. Pfau
%A C. Bohley
%A G. Seifert
%A S. Schweizer
%J Dataset Papers in Science
%D 2013
%R 10.1155/2013/236421
%X A Judd-Ofelt analysis is performed to calculate the optical properties of Nd3+ ions embedded in a fluorozirconate glass matrix. The changes in the Judd-Ofelt parameters were determined as a function of the size of BaCl2 nanocrystals grown inside the matrix. From these data, the radiative decay rates and the branching ratios of every transition in the energy range from 25.000£¿cm£¿1 to the ground state are calculated. This was accomplished for samples containing nanocrystals with average sizes ranging from 10 to 40£¿nm. 1. Introduction Photonic glasses doped with rare-earth ions such as erbium, neodymium, or europium gather widespread interest because of their applicability in photonic devices. Application as, for example, the active ion in a laser medium or as frequency converter in up- and downconverters [1, 2] requires efficient radiative decays of the ion with only minor losses to multiphonon relaxation (MPR). Therefore, the ion needs to be embedded in a low phonon energy environment which still remains both stable and transparent. Among appropriate materials are fluorozirconate (FZ) glasses with maximum phonon energies of less than 580£¿cm£¿1 [3¨C5]. They have already proved to be a convenient choice for several applications. As shown previously [6, 7], a uniform growth of BaCl2 nanocrystals inside such glasses can be induced by thermal treatment as soon as additional chloride is introduced at the expense of fluoride. Since BaCl2 has a maximum phonon energy on the order of 200£¿cm£¿1 [3, 8], MPR is rendered even less probable and, thus, rare-earth ions tend to favor radiative decays [6, 7, 9]. The optical properties of Nd3+-doped fluorochlorozirconate (FCZ) glasses with differently sized BaCl2 nanocrystals were studied with Judd-Ofelt theory. The sizes of the embedded nanocrystals were obtained from X-ray diffraction in combination with Scherrer analysis. It is known that Nd3+ ions are strongly affected by the BaCl2 nanocrystals, but until now only speculations were possible as to the location of rare-earth ions at the edge of nanocrystals or even the possible inclusion into them [9, 10]. From Judd-Ofelt [11¨C13] analysis, the phenomenological Judd-Ofelt parameters can be determined. With them a quantitative measure for the influence of BaCl2 nanocrystals on the Nd3+ can be established (see [14] for a detailed discussion). Here, the radiative decay rates for each transition were calculated and are given in a compressed form. 2. Methodology Experimental details are as follows.The FCZ glass samples [14] investigated in this study are comprised of
%U http://www.hindawi.com/journals/dpis/2013/236421/