Spectral Power Distribution And Quantum Yield Of Sm³⁺ And Eu³⁺-doped Bismuth Tellurite Glasses Under The Excitation Of Violet LED

Glasses doped with various rare-earth ions are important materials for fluorescent displaydevices, optical detectors, bulk lasers, optical fibers, waveguide lasers and optical amplifiers.Of the oxide glasses, tellurite glasses catch much attention in recent years because theirmaximum phonon energy is lower than those in silicate, borate, phosphate and germanateglasses. Rare-earth ions can be expected that the non-radiative loss to the lattice will be smalland the fluorescence quantum efficiency will be high in tellurite glasses. In the mean time,barium-and bismuth-containing heavy metal tellurite glasses are considered to be theoptimizing candidates for designing optical devices since the barium and bismuth not onlyimprove the glasses stability, chemical resistance and optical refractive index, but also cause afurther reduction in the maximum-energy phonon density resulting in an obviousimprovement of upconversion fluorescence efficiency. With the increasing demand of variousfluorescent devices and visible lasers, further investigations in the rare-earth ions, such asSm³⁺and Eu³⁺ions, are becoming more significant. In the rare-earth family, Sm³⁺andEu³⁺ions are rather active members and usually act as a powerful emitting center for makingfluorescent display devices, optical detectors, bulk lasers, optical fibers, waveguide lasers andoptical amplifiers.A new method for measuring spectral power distribution in Sm³⁺and Eu³⁺-dopedbismuth tellurite glass with higher refractive index and lower phonon energy by usingintegrating sphere was introduced and designed at the first time. Fluorescence measure systemwas constituted by integrating sphere of10-inch diameter, which was connected to a CCDdetector. A standard halogen lamp was used to calibrate measurement system and theauxiliary standard halogen lamp was employed for collating inner change in integratingsphere. Total radiant flux, total luminous flux and total quantum yield were calculated byluminous flux distribution and photon distribution, which were derived from spectral powerdistribution. In this paper, integrating sphere-method was applied to measure luminescenceparameters of the multichannel transition emissions in Sm³⁺and Eu³⁺, and it was considered as an accurate way to characterize luminescence parameters for luminescence and lasermaterial. The new measurement method and research results provide the theoretical basis andpledge of new material for new types of fluorescence display devices and development ofrare-earth doped new laser glasses and fibers.In this work, alkali-barium-bismuth-tellurite （LKBBT） glasses were designed based upontraditional tellurite glasses. Optical and luminescence properties of rare-earth ions in bismuthtellurite glasses have been studied at room temperature. The results and progresses obtainedare as follows.1. Sm³⁺-doped5Li2O-5K2O-5BaO-10Bi2O3-75TeO2（LKBBT-Ⅰ）glass with highrefractive index has been synthesized. Total radiant flux, total luminous flux and totalquantum yield were calculated by luminous flux distribution and photon distribution, whichwere derived from spectral power distribution. Under the violet LED emitting, the totalquantum yield of the visible fluorescence of Sm³⁺has been calculated to be4.07%. In thespectral region of five emission bands （550～780nm）, the total radiant flux has been derivedto be55μW and occupy4.07%of the whole. In the visible spectral region （380～780nm）,total luminous flux has been calculated to be0.02lm.2. Eu³⁺-doped5Li2O-5K2O-5BaO-10Bi2O3-75TeO2（LKBBT-Ⅱ）glass with highrefractive index has been synthesized. The spectral power distributions of the sample underthe violet LED emitting have been determined, and the total quantum yield of the visiblefluorescence of Eu³⁺and main emission band （5D07F2） have been calculated to be4.36%and2.29%, respectively. In the spectral region of360～780nm, the total radiant flux has beencalculated to be1053μW, and in the spectral region of five emission bands （575～715nm） ithas been derived to be57μW and occupy5.41%of the whole. In the visible spectral region,total luminous flux has been calculated to be0.021lm.