For the first time, to the best of our knowledge, laser cooling is reported in a silica optical fiber. The fiber has a 21-µm diameter core doped with 2.06 wt.% ${{\rm Yb}^{3 + }}$Yb3+ and co-doped with ${{\rm Al}_2}{{\rm O}_3}$Al2O3 and ${{\rm F}^ - }$F- to increase the critical quenching concentration by a factor of 16 over the largest reported values for the Yb-doped silica. Using a custom slow-light fiber Bragg grating sensor, temperature changes up to $ - {50}\;{\rm mK}$-50mK were measured with 0.33 W/m of absorbed pump power per unit length at 1040 nm. The measured dependencies of the temperature change on the pump power and the pump wavelength are in excellent agreement with predictions from an existing model, and they reflect the fiber's groundbreaking quality for the radiation-balanced fiber lasers.

中文翻译：

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在大气压下在石英光纤中进行激光冷却。

据我们所知，这是第一次在石英光纤中报道了激光冷却。光纤具有直径为21 µm的纤芯，掺杂有2.06 wt。％$ {{\ rm Yb} ^ {3 +}} $ Yb3 +并共掺有$ {{\ rm Al} _2} {{\ rm O} _3} $ Al2O3和$ {{\ rm F} ^-} $ F-使临界淬火浓度比掺Yb的二氧化硅的最大报道值增加16倍。使用定制的慢光纤布拉格光栅传感器，在1040 nm处，每单位长度的吸收泵浦功率为0.33 W / m，测量的温度变化高达$-{50} \; {\ rm mK} $-50mK。温度变化对泵浦功率和泵浦波长的依赖关系与现有模型的预测非常吻合，它们反映了光纤在辐射平衡光纤激光器中的突破性品质。