Guozhong Ren

2.7 μm emission of Nd3+, Er3+ codoped tellurite glass

In this paper, we report on the observation of enhanced 2.7 mum midinfrared emission under 800 nm excitation in a Nd{sup 3+}/Er{sup 3+} codoped tellurite glass. It is also found that the green upconversion emissions from Er{sup 3+} are effectively restricted, meanwhile the {sup 4}I{sub 13/2} level of Er{sup 3+} is depopulated in the Nd{sup 3+}/Er{sup 3+} codoped tellurite glass. These results suggest that the midinfrared emission can be achieved in the oxyfluoride glasses and that codoping with Nd{sup 3+} can greatly improve the midinfrared emission performance.In this paper, we report on the observation of enhanced 2.7 μm midinfrared emission under 800 nm excitation in a Nd3+/Er3+ codoped tellurite glass. It is also found that the green upconversion emissions from Er3+ are effectively restricted, meanwhile the I413/2 level of Er3+ is depopulated in the Nd3+/Er3+ codoped tellurite glass. These results suggest that the midinfrared emission can be achieved in the oxyfluoride glasses and that codoping with Nd3+ can greatly improve the midinfrared emission performance.

Temperature dependence of structural and luminescent properties of Tb3+ doped YPO4

The solution precipitation is used to synthesize the Tb doped yttrium phosphates. The as-synthesized is the monoclinic phased YPO4×2H2O with churchite-type structure, which is transformed to the tetragonal phased YPO4 with xenotime-type structure as the temperature approaches 200°C during the thermal treatment process. This phase transformation process can not be observed in some routes that need a higher synthetic temperature, in which, only a high-temperature phase is obtained. The luminescent efficiency dependence on the heat-treatment temperature is investigated. The luminescent efficiency presents a two-step increase respectively around 300 and 700°C. Results indicate that the significant increase of luminescent efficiency at 300°C is not related to the phase structure transformation, but to the decrease of OH- ions content, and that the significant increase of luminescent efficiency at 700°C is related to the increase of crystallinity, which may increase the absorption to VUV light.

Spectroscopic investigations of Er 3+ doped Bi 2 O 3 -B 2 O 3 -SiO 2 glass

From the optical absorption measurements, the Judd-Ofelt parameters were computed using Judd-Ofelt theory. According to the radiative lifetime obtained from the Judd-Ofelt parameters and the measured lifetime, the1.5μm quantum efficiency was calculated. The quenching effect of OH upon the lifetime of 1.5μm emission was investigated. From the absorption sideband measurement of glass host, the value of optical band gap was estimated. The McCumber theory was used to calculate the stimulated emission cross-section and in approximate agreement with experimental one if the emission spectrum could be obtained accurately. The gain coefficient spectra were computed.