SHARP R-LINES IN ABSORPTION AND EMISSION OF CR3+ IN STOICHIOMETRIC (VTE) LINBO3

Citation
C. Fischer et al., SHARP R-LINES IN ABSORPTION AND EMISSION OF CR3+ IN STOICHIOMETRIC (VTE) LINBO3, Radiation effects and defects in solids, 135(1-4), 1995, pp. 697-700
Citations number
7
Categorie Soggetti
Physics, Condensed Matter","Nuclear Sciences & Tecnology
ISSN journal
10420150
Volume
135
Issue
1-4
Year of publication
1995
Pages
697 - 700
Database
ISI
SICI code
1042-0150(1995)135:1-4<697:SRIAAE>2.0.ZU;2-S
Abstract
R-line absorption and luminescence spectra of Cr3+ doped LiNbO3 show a distinct dependence on crystal stoichiometry. In the Cr3+ R-line regi on around 730 nm, up to five transitions can be observed in absorption and emission. In stoichiometric LiNbO3:Cr crystals the line width (FW HM) in both absorption and emission decreases by about a factor of 2.5 in comparison with the same transitions in congruent samples. The emi ssion line at lowest energy in the R-line spectrum (lambda = 734.5 nm) disappears completely in stoichiometric LiNbO3:Cr. This results, disc ussed together with models dealing with charge compensated Cr3+ pairs on Li and Nb sites and unpaired Cr3+ on Li site, is indicating a vanis hing of the unpaired Cr-Li(3+) with increasing [Li]/[Nb] ratio. Lumine scence lifetime measurements in stoichiometric LiNbO3:Cr reveal values similar to results for congruent material of tau = 295 mu s for the 7 31 nm line and tau = 268 mu s for the 735 nm line, underlining the R-l ine character of these transitions.