Schmid J H, Sinclair W, García J, Janz S, Lapointe J, Poitras D, Li Y, Mischki T, Lopinski G, Cheben P, Delâge A, Densmore A, Waldron P, Xu D-X
Institute for Microstructural Sciences, National Research Council Canada, Ottawa, Ontario, K1A 0R6.
Opt Express. 2009 Sep 28;17(20):18371-80. doi: 10.1364/OE.17.018371.
We present experimental and theoretical results of label-free molecular sensing using the transverse magnetic mode of a 0.22 mum thick silicon slab waveguide with a surface grating implemented in a guided mode resonance configuration. Due to the strong overlap of the evanescent field of the waveguide mode with a molecular layer attached to the surface, these sensors exhibit high sensitivity, while their fabrication and packaging requirements are modest. Experimentally, we demonstrate a resonance wavelength shift of approximately 1 nm when a monolayer of the protein streptavidin is attached to the surface, in good agreement with calculations based on rigorous coupled wave analysis. In our current optical setup this shift corresponds to an estimated limit of detection of 0.2% of a monolayer of streptavidin.
我们展示了利用0.22微米厚的硅平板波导的横向磁模式进行无标记分子传感的实验和理论结果，该波导表面带有以导模共振配置实现的光栅。由于波导模式的倏逝场与附着在表面的分子层有很强的重叠，这些传感器具有高灵敏度，同时其制造和封装要求不高。在实验中，当一层链霉亲和素蛋白附着在表面时，我们证明共振波长偏移约1纳米，这与基于严格耦合波分析的计算结果非常吻合。在我们当前的光学装置中，这种偏移对应于链霉亲和素单层0.2%的估计检测限。
