Eur. Phys. J. Appl. Phys.
Volume 41, Number 2, February 2008
|Page(s)||143 - 149|
|Section||Characterization of Materials: Imaging, Microscopy and Spectroscopy|
|Published online||06 February 2008|
Observation of ESA, ET and thermally enhanced frequency upconversion in Nd3+: LiTeO2 glass
Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University,
Varanasi – 221005, India
Corresponding author: email@example.com
Accepted: 19 November 2007
Published online: 6 February 2008
Infrared to visible upconversion emission bands are observed in Nd3+: LiTeO2 glass at 430, 482, 525, 535, 580, 600, 664 and 766 nm wavelengths due to the 2P1/2 4I9/2, 2P1/2 4I11/2, 2P1/2 4I13/2, 4G7/2 4I9/2, 2P1/2 4I15/2, 4G7/2 4I11/2 & 4G5/2+2G7/2 4I9/2, 4G7/2 4I13/2 and 4G7/2 4I15/2 transitions, respectively. Mechanisms involved in these upconversion emissions are shown to either involve excited state absorption or energy transfer depending upon the concentration of the rare earth ions. The emission bands at 755 and 968 nm are also observed due to the thermally excited phonon absorption, on excitation with 800 nm wavelength. A 90 fold enhancement in the intensity of anti-Stokes emission at 755 nm is observed in this glass when temperature is raised from 298 to 523 K. Fluorescence intensity ratio (FIR) and sensitivity (S) of the two thermally coupled levels viz. 4F3/2 and 4F5/2 are calculated at different temperatures and results show that these levels could act as temperature sensor in tellurite host. Lifetimes of the excited levels 2P1/2, 4G7/2, 4F3/2, 4F5/2 and 4F7/2 involved in the emission process are also determined and their temperature dependence is described.
PACS: 33.50.Dq – Fluorescence and phosphorescence spectra / 32.80.Wr – Other multiphoton processes
© EDP Sciences, 2008
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