Mid-infrared emission characteristic and energy transfer of Ho3+-doped tellurite glass sensitized by Tm 3+.

G X Chen, Q Y Zhang, G F Yang, Z H Jiang

Index: J. Fluoresc. 17(3) , 301-7, (2007)

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Abstract

We report on 2.0-microm emission characteristic and energy transfer of Ho3+-doped tellurite glass sensitized by Tm3+ upon excitation of a conventional 808 nm laser diode. The Judd-Ofelt strength parameters, spontaneous radiative transition probabilities and radiative lifetime of Ho3+ have been calculated from the absorption spectra by using the Judd-Ofelt theory. Significant enhancement of 2.0-microm emission of Ho3+ has been observed with increasing Tm3+ doping up to 0.7 mol%. The energy transfer coefficient of the forward Tm3+-->Ho3+ is approximately 17 times larger than that of the backward Tm3+<--Ho3+ energy transfer. Our result indicates that the maximum gain of 2.0-microm emission, assigned to the transition of (5)I7-->(5)I8 of Ho3+, might be achieved from the tellurite glass at the concentration of 0.5 mol% of Tm2O3 and 0.15 mol% of Ho2O3. The high gain coefficient and quantum efficiency (1.16) along with the large value of the product of the stimulated emission cross-section and the measured radiative lifetime (4.12 x 10(-27) m(2)s) of the Ho3+/Tm3+-codoped tellurite glasses might find potential applications in efficient 2.0-microm laser.