重金属碲酸盐玻璃中Ho~(3+)的红外辐射特性

制备了高折射率Ho3+单掺和Ho3+/Yb3+共掺低声子能量重金属碲酸盐玻璃.根据Judd-Ofelt理论对吸收光谱进行拟合,求得Ho3+强度参数Ωt(t=2,4,6)分别为4.373×10-20,1.906×10-20和1.451×10-20cm2,并进一步计算了Ho3+在红外区各能级跃迁的振子强度、自发辐射跃迁概率、辐射寿命和荧光分支比等光谱参数.982 nm激发下,铋碲酸盐玻璃中Yb3+直接敏化Ho3+,在红外区产生有效红外发射.Ho3+吸收与发射截面在1.95和2.05μm处分别高达5.63×10-21和6.24×10-21cm2,大于Ho3+掺杂磷酸盐和氟化物玻璃,这有利于降低激光抽运阈值,实现高效Ho3+激光输出.较低的声子能量和较大的发射截面表明,Ho3+/Yb3+共掺杂铋碲酸盐玻璃有望成为良好的红外激光工作物质.

Infrared Radiative Characteristic of Ho~(3+) 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 Ω2, Ω4 and Ω6 were derived to be 4.373 10-20, 1.906 10-20 and 1.451 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 10-21 cm2 at 1.95 mm and 6.24 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.