Ultralow threshold green lasing and optical bistability in ZBNA (ZrF4–BaF2–NaF–AlF3) microspheres
Ultralow threshold green lasing and optical bistability in ZBNA (ZrF4–BaF2–NaF–AlF3) microspheres
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DOI：
10.1063/1.3277024
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发表时间：
2010-02
影响因子：
3.2
通讯作者：
Yuqiang Wu;J. Ward;Síle Nic Chormaic
中科院分区：
文献类型：
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作者：
Yuqiang Wu;J. Ward;Síle Nic Chormaic
研究了一种新型氟锆酸盐Er3+掺杂玻璃ZBNA （ZrF4-BaF2-NaF-AlF3）制备的活性微球在978 nm处通过锥形光纤泵浦产生的上转换激光和荧光。测量了550 nm发射的超低绿色激光阈值为~ 3 μW。这比先前报道的ZBLAN （ZrF4-BaF2-LaF3-AlF3-NaF）微球低一个数量级。报道了ZBNA微球中的光学双稳效应，讨论了双稳机制，并将其归因于球的热膨胀引起的窃窃廊模式的移位，其中加热是通过光泵浦在978 nm左右实现的。研究了双稳性对上转换激光的影响，并报道了微球内存在多个双稳性环路。
Upconversion lasing and fluorescence from active microspheres fabricated from a novel fluorozirconate, Er3+ doped glass, ZBNA (ZrF4–BaF2–NaF–AlF3), when pumped at 978 nm via a tapered optical fiber is demonstrated. An ultralow, green lasing threshold of ∼3 μW for 550 nm emissions is measured. This is one order of magnitude lower than that previously reported for ZBLAN (ZrF4–BaF2–LaF3–AlF3–NaF) microspheres. Optical bistability effects in ZBNA microspheres are reported and the bistable mechanism is discussed and attributed to shifts of the whispering gallery modes due to thermal expansion of the sphere, where heating is achieved by optical pumping around 978 nm. The effect of the bistability on the upconversion lasing is examined and we report multiple bistability loops within the microspheres.