涂覆高折射率树脂薄膜的聚合物波导传感器的制备

Preparation of high-refractive-index resin film coated polymer waveguide fiber sensor

倏逝波的强弱决定了波导型倏逝波传感器的探测极限。在波导表面涂覆一层高折射率树脂薄膜,提高光波导外倏逝波的占比。高折射率薄膜的涂覆可以大幅度改变波导中的光场分布,并提高倏逝波强度。通过研究不同折射率下倏逝波占比与镀膜厚度间的相互关系,得到了不同折射率下的覆膜最佳厚度。通过激光诱导波导自成型技术在聚合物波导上涂覆了一层折射率为1.6,厚度为300 nm的树脂薄膜。光谱测量结果表明,经过薄膜涂覆后,传感器对罗丹明B水溶液的吸收检测极限提高至1×10^(-9)g/mL,比未覆膜传感器高了10倍。该传感器成本低、体积小、制作简单、灵敏度高,在各个领域都拥有广阔的应用前景。

The sensibility of a waveguide evanescent wave sensor is limited by its evanescent wave intensity. To improve the sensibility of the sensor, the evanescent wave intensity of the waveguide was enhanced by designing a high-refractive-index resin layer on the surface of the waveguide. To optimize the layer thickness, the relationship between the evanescent wave ratios and the layer thicknesses under different refractive index values was studied. A laser-induced waveguide selfwritten technique was utilized to fabricate an evanescent wave sensor by coating a layer on the waveguide with refractive index of 1.6 and a thickness of 300 nm, respectively. The UV-Vis spectral measurement results show that after the layer coating, the absorption detection limit of Rhodamine B aqueous solution is increased to 1×10^(-9) g/mL, which is 10 times enhanced than that of the uncoated sensor. The sensor has the merits of low cost, small size, simple fabrication and high sensitivity, which has broad application prospects in various fields.