Homogeneity of bismuth-distribution in bismuth-doped alkali germanate laser glasses towards superbroad fiber amplifiers.
Homogeneity of bismuth-distribution in bismuth-doped alkali germanate laser glasses towards superbroad fiber amplifiers.
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DOI：
10.1364/oe.23.012423
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发表时间：
2015-05
期刊：
影响因子：
3.8
通讯作者：
Yanqi Zhao;L. Wondraczek;A. Mermet;M. Peng;Qinyuan Zhang;J. Qiu
中科院分区：
文献类型：
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作者：
Yanqi Zhao;L. Wondraczek;A. Mermet;M. Peng;Qinyuan Zhang;J. Qiu
与稀土掺杂玻璃相比，铋掺杂玻璃有望实现超宽带近红外（NIR）光电发射和光学放大方面的潜在应用。然而，光学活性铋中心对周围基质的性质以及加工条件极其敏感。这使得这类材料的开发变得非常复杂，因为功能器件需要对铋物质的氧化还原状态及其在整个材料中的分布进行非常微妙的调整。它还在很大程度上限制了玻璃纤维的一些传统加工路线，这些路线从气相沉积开始，可能需要非常高的加工温度。在这里，我们研究了熔融时间和碱添加对熔融锗酸盐玻璃与铋相关的近红外光致发光的影响。我们表明，熔化时间对铋相关吸收和近红外光发射的影响主要是通过铋挥发来实现的。添加碱金属氧化物作为助熔剂，可以降低熔体粘度以降低玻璃熔化温度或熔化时间或两者。然而，与此同时，碱的添加也会导致平均场碱度增加，这可能会降低与铋相关的近红外发射的强度。优先使用Li2O而不是Na2O或K2O代表了上述因素之间的最佳权衡，因为其局部效应可能与普遍假设的更基本基体成分的负面影响趋势相反。这一观察结果为具有高效近红外光电发射和高光学均匀性的熔融衍生双掺杂玻璃的设计提供了重要指导。
Compared to rare-earth doped glasses, bismuth-doped glasses hold promise for super-broadband near-infrared (NIR) photoemission and potential applications in optical amplification. However, optically active bismuth centers are extremely sensitive to the properties of the surrounding matrix, and also to processing conditions. This is strongly complicating the exploitation of this class of materials, because functional devices require a very delicate adjustment of the redox state of the bismuth species, and its distribution throughout the bulk of the material. It also largely limits some of the conventional processing routes for glass fiber, which start from gas phase deposition and may require very high processing temperature. Here, we investigate the influence of melting time and alkali addition on bismuth-related NIR photoluminescence from melt-derived germanate glasses. We show that the effect of melting time on bismuth-related absorption and NIR photoemission is primarily through bismuth volatilization. Adding alkali oxides as fluxing agents, the melt viscosity can be lowered to reduce either the glass melting temperature, or the melting time, or both. At the same time, however, alkali addition also leads to increasing mean-field basicity, what may reduce the intensity of bismuth-related NIR emission. Preferentially using Li2O over Na2O or K2O presents the best trade-off between those above factors, because its local effect may be adverse to the generally assumed trend of the negative influence of more basic matrix composition. This observation provides an important guideline for the design of melt-derived Bi-doped glasses with efficient NIR photoemission and high optical homogeneity.