Shi Huimin, He Jiangyong, Guo Huiyi, Liu Xiaoqi, Wang Zhi, Liu Yan-Ge
Opt Express. 2021 Mar 29;29(7):10077-10088. doi: 10.1364/OE.418936.
A single-resonator, stable dual-longitudinal-mode optofluidic microcavity laser based on a hollow-core microstructured optical fiber is proposed and experimentally demonstrated. The resonator and microfluidic channel are integrated in the hollow-core region of the fiber, inside which a hexagonal silica ring is used as the only resonator of the laser. Experimental results show that with mixing a small amount of Rhodamine B into a 1 mM Rhodamine 6G solution to form a dual-dye solution as a gain medium, the laser obtained by the method of lateral pumping can operate at dual longitudinal modes, with a threshold of 90 nJ/mm. By adjusting the concentration of Rhodamine B, the lasing wavelength of the laser and the power ratio of the two wavelengths can be controlled. And because the laser emission is co-excited by different kinds of dye molecules, the mode competition is diminished, enabling the simultaneously efficient optical gain and therefore lasing at dual longitudinal modes stably with a maximum lasing intensity fluctuation of 3.2% within 30 minutes even if the dual longitudinal modes have the same linear polarization states. This work can open up promising opportunities for diverse applications in biosensing and medical diagnosis with high sensitivity and integrated photonics with compact structure.
提出并通过实验证明了一种基于空心微结构光纤的单谐振器、稳定双纵模光流体微腔激光器。谐振器和微流体通道集成在光纤的空心区域内，其中一个六边形二氧化硅环用作激光器的唯一谐振器。实验结果表明，将少量罗丹明B混入1 mM罗丹明6G溶液中形成双染料溶液作为增益介质，通过侧向泵浦方法获得的激光器可以在双纵模下工作，阈值为90 nJ/mm。通过调节罗丹明B的浓度，可以控制激光器的激射波长和两个波长的功率比。并且由于激光发射由不同种类的染料分子共同激发，模式竞争减弱，从而实现了高效的光学增益，因此即使双纵模具有相同的线性偏振态，也能在双纵模下稳定激射，在30分钟内最大激射强度波动为3.2%。这项工作可为生物传感和高灵敏度医学诊断以及结构紧凑的集成光子学等多种应用开辟广阔前景。
