Spectroscopic properties of a Tm3+: Bi2TeO5 single crystal

摘要

Single crystal of bismuth tellurite Bi2TeO5 (BTO) doped with trivalent thulium (TM3+) was grown by the Czochralski method and investigated by spectroscopic techniques (absorption, emission). Absorption and emission of the Tm:BTO crystal collected in the VIS-IR spectral range are presented. Spectroscopic features were investigated as a function of the excitation light polarisation (E parallel to X, Y, and Z axis of optical indicatrix) and sample temperature. The oscillator strength of the H-3(6) -> F-3(4), transition at 1.7 mu m was determined by numerical integration of the X, Y and Z polarised absorption spectra. The obtained values are: P-X = 4.7 x 10(-6), P-Y = 6.8 x 10(-6) and P-Z = 5.9 x 10(-6) that gives a mean value P-mean = 5.8 x 10(-6). Emission was observed from the (1)G(4) and H-3(4) levels. The H-3(4) and (1)G(4) excited state dynamics was studied. Decay curves and time constants of luminescence were collected at 5 and 300 K and analysed. The F-3(4)-> H-3(6) luminescence at around 1.8 mu m was too weak to be acquired from the low concentrated sample. However, based on optical data it was possible to estimate the radiative probability A(rad) of this transition and the F-3(4) radiative lifetime. The resultant values are: A(rad) = 668 +/- 0.4 s(-1) and tau(rad) = 1.5 ms. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.