[Infrared radiative characteristic of Ho3+ in heavy metal tellurite glasses].

Ho3+ doped and Ho3+/Yb3+ co-doped low phonon heavy metal tellurite glasses with large refractive indices were designed and fabricated. Based on optical absorption, Judd-Ofelt parameters Omega2, Omega4 and Omega6 were derived to be 4.373 x 10(-20), 1.906 x 10(-20) and 1.451 x 10(-20) cm2, respectively. Then the radiative transition probabilities, radiative lifetimes and fluorescence branching ratios were calculated. The efficient infrared emission in Ho3+/Yb3+ co-doped bismuth tellurite glass system was recorded under the pumping of a 982 nm diode laser and Yb3+ was considered to be a preferable sensitizer for catching remarkable pumping energy and transferring considerable energy to Ho3+. The maximum absorption and calculated emission cross sections are 5.63 x 10(-21) cm2 at 1.95 mm and 6.24 x 10(-21) cm2 at 2.05 mm, respectively, which are larger than the values in phosphate and fluoride glasses, and are beneficial in lowing laser threshold as well as realizing efficient laser output of Ho3+. Low maximum photon energy and high emission cross sections indicate that Ho3+/Yb3+ co-doped low phonon bismuth tellurite glasses will be promising infrared laser materials.