Optofluidic laser is an emerging method for biochemical sensing. The topic on, which kind of structure is the best to integrate the laser resonator and microfluidic channel, is worth to be explored. Here, we report a hollow optical fiber optofluidic laser based on a dye-doped polymer film. This fiber microstructure is a promising candidate that serves both as a laser microresonator and a compact microfluidic channel. The refractive index of the polymer film is higher than silica so that the whispering gallery mode can be supported. The coating process is explored in detail. The laser spectra and threshold properties of the HOF microlaser are investigated. The dye-doped polymer film can be controlled to be as thin as 1.6 μm and a threshold of below 1 μJ/mm2 can be reached. Thanks to the strong light-liquid interaction enabled by the polymer coating on the inner interface of HOF, sensitive refractive index detection is demonstrated by monitoring the laser wavelength shift, which has the potential for wavelength division multiplexing. This laser sensor is promising for label-free biochemical detection.

中文翻译：

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用于折射率传感的聚合物涂层中空光纤光流体激光器

光流体激光是一种新兴的生化传感方法。哪种结构最适合将激光谐振腔和微流体通道集成在一起，值得探讨。在这里，我们报告了一种基于染料掺杂聚合物薄膜的中空光纤光流体激光器。这种光纤微结构是一种很有前途的候选者，既可用作激光微谐振器，又可用作紧凑的微流体通道。聚合物薄膜的折射率高于二氧化硅，因此可以支持回音壁模式。详细探讨了涂层工艺。研究了 HOF 微型激光器的激光光谱和阈值特性。染料掺杂的聚合物薄膜可以控制为1.6μm的薄，并且可以达到低于1μJ/mm2的阈值。由于 HOF 内界面上的聚合物涂层实现了强烈的光-液相互作用，通过监测激光波长偏移证明了灵敏的折射率检测，这具有波分复用的潜力。这种激光传感器有望用于无标记生化检测。