SAIP2014

Laser-selective excitation and polarisation studies of BaF₂: Tm³⁺ single crystals

11 Jul 2014, 11:30

20m

D Les 201

Oral Presentation Track A - Division for Physics of Condensed Matter and Materials DPCMM1

Speaker

Dr Marjorie Mujaji (University of the Witwatersrand)

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Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

Site-selective laser excitation studies of BaF₂:Tm³⁺ single crystals performed at temperatures ranging from 10 K to 75 K are reported. There is a single dominant centre at the dopant concentrations of up to 0.1 mole% used. All the crystal-field energy levels for three multiplets (³H₆, ³H₄ and ³F₂) of the centre and the fluorescence lifetime of the ³H₄ multiplet are presented. From polarisation ratio measurements in <111>-oriented crystals the dominant centre is confirmed to be of C_3v symmetry, with the charge-compensation interstitial F^- ion in the next nearest neighbour position to the Tm³⁺ ion. Symmetry labels (irrep labels) have been assigned to the crystal-field energy levels. Vibronic coupling is apparent.