微流道中消逝场激励的荧光光源研究

Study on Fluorescent Radiation Excited by Evanescent Field in a Microfluidic Channel

将石英裸光纤植入聚二甲基硅氧烷(PDMS)基片的微流道中,采用沿光纤轴向光激励、消逝场激励染料分子的方式,在基片微流道中获得均匀的荧光辐射。实验发现,在激励光强确定的条件下,荧光辐射的强度与染料溶液的浓度呈线性正相关关系,而与包层溶液的折射率呈非线性正相关的关系。用消逝波激励荧光的辐射理论,很好地解释了实验结果。

A bare quartz optical fiber is embedded in a polydimethylsiloxane（PDMS）substrate microfluidic channel,pumped by a continuous wave laser along the fiber axis,and the dye fluorescence excited by evanescent field of the pump beam has been investigated.As the evanescent field of the pump beam is homogeneous along the fiber axis,it is found that the fluorescent emission from the rim of fiber is uniform along the microfluidic channel.The experimental results show that the fluorescent emission intensity strongly depends on the dye concentration and the refractive index of the dye solution,and with the increase of the dye concentration and the refractive index of dye solution,the emitted fluorescent intensity increases accordingly.The observed phenomena have been successfully explained based on the mechanism of evanescent wave pumping fluorescent radiation.