Electrical and Electronic Engineering Department, Public University of Navarre, Pamplona, Navarre, Spain.
Opt Lett. 2013 Jul 15;38(14):2481-3. doi: 10.1364/OL.38.002481.
This Letter, presents the fabrication of lossy mode resonance (LMR) devices based on titanium dioxide (TiO2)/ poly(sodium 4-styrenesulfonate) (PSS) coatings deposited on side-polished D-shaped optical fibers. TiO2 thin films have been obtained by means of the layer-by-layer (LbL) self-assembly technique. LbL enables us to produce smooth and homogeneous coatings on the polished side of the fiber. This permits us to couple light from the waveguide to the TiO2-coating/external medium region at specific wavelength ranges. The generation of LMRs depends on the coating thickness, so that thicker coatings can produce more resonances. LMRs are sensitive to the external medium refractive index, which allows its utilization as refractometers. The characteristic D-shaped architecture of the devices employed in this Letter enables us to distinguish TE and TM polarizations, which had not been possible before with regular optical fibers due to their cylindrical symmetry. The results presented here show for the first time the experimental demonstration of the generation of LMRs produced by both TM and TE polarizations. More specifically, for these TiO2/PSS thin films, the TM and TM modes of the LMRs show a wavelength shift of 226 nm for the first-order LMR and 56 nm for the second-order LMR.
这封信介绍了基于涂覆在侧边抛磨 D 型光纤上的二氧化钛 (TiO2)/聚(4-苯乙烯磺酸钠) (PSS) 涂层的损耗型模式共振 (LMR) 器件的制造。TiO2 薄膜是通过层层自组装 (LbL) 技术获得的。LbL 使我们能够在光纤的抛光侧生产出光滑均匀的涂层。这使得我们能够在特定的波长范围内将光从波导耦合到 TiO2 涂层/外部介质区域。LMR 的产生取决于涂层厚度，因此较厚的涂层可以产生更多的共振。LMR 对外界介质折射率敏感，这使其可用作折射率计。本信中使用的器件的独特 D 形结构使我们能够区分 TE 和 TM 偏振，这在以前由于圆柱形对称而无法用普通光纤实现。这里呈现的结果首次展示了由 TM 和 TE 偏振产生的 LMR 的实验演示。更具体地说，对于这些 TiO2/PSS 薄膜，一阶 LMR 的 TM 和 TM 模式的波长位移为 226nm，二阶 LMR 的波长位移为 56nm。
