Yang Jingjing, Francescato Yan, Chen Dezhang, Yang Jianfeng, Huang Ming
Opt Express. 2015 Apr 6;23(7):8583-9. doi: 10.1364/OE.23.008583.
Unambiguous identification of low concentration chemical mixtures can be performed by broadband enhanced infrared absorption (BEIRA). Here we propose and numerically study a corrugated parallel plate waveguide (CPPW) with gradient grooves which is capable of directly converting transmission modes to surface plasmon modes and could hence serve as a powerful chemical sensor. Such a waveguide can be designed to exhibit a wide pass band covering an extended portion of a molecule absorption spectrum. Broadband sensing of toluene and ethanol thin layers is demonstrated by calculating the transmission coefficient of the waveguide and is shown to correspond exactly to their infrared spectra. In addition, the upper limit and the lower limit of the bandgap are mainly dependent on the minimum and maximum groove height, respectively, which provide an effective way of tuning the working frequency of the device in order to support surface plasmon modes within a desired frequency range according to a specific application.
低浓度化学混合物的明确识别可以通过宽带增强红外吸收（BEIRA）来实现。在此，我们提出并对一种具有梯度凹槽的波纹平行板波导（CPPW）进行了数值研究，该波导能够直接将传输模式转换为表面等离子体模式，因此可以用作强大的化学传感器。这种波导可以设计成具有覆盖分子吸收光谱扩展部分的宽通带。通过计算波导的传输系数，展示了对甲苯和乙醇薄层的宽带传感，并且显示出与它们的红外光谱完全对应。此外，带隙的上限和下限分别主要取决于最小和最大凹槽高度，这提供了一种有效的方法来调整器件的工作频率，以便根据特定应用在所需频率范围内支持表面等离子体模式。
