Huang Yin, Min Changjun, Dastmalchi Pouya, Veronis Georgios
Opt Express. 2015 Jun 1;23(11):14922-36. doi: 10.1364/OE.23.014922.
We introduce slow-light enhanced subwavelength scale refractive index sensors which consist of a plasmonic metal-dielectric-metal (MDM) waveguide based slow-light system sandwiched between two conventional MDM waveguides. We first consider a MDM waveguide with small width structrue for comparison, and then consider two MDM waveguide based slow light systems: a MDM waveguide side-coupled to arrays of stub resonators system and a MDM waveguide side-coupled to arrays of double-stub resonators system. We find that, as the group velocity decreases, the sensitivity of the effective index of the waveguide mode to variations of the refractive index of the fluid filling the sensors as well as the sensitivities of the reflection and transmission coefficients of the waveguide mode increase. The sensing characteristics of the slow-light waveguide based sensor structures are systematically analyzed. We show that the slow-light enhanced sensors lead to not only 3.9 and 3.5 times enhancements in the refractive index sensitivity, and therefore in the minimum detectable refractive index change, but also to 2 and 3 times reductions in the required sensing length, respectively, compared to a sensor using a MDM waveguide with small width structure.
我们介绍了慢光增强型亚波长尺度折射率传感器，该传感器由夹在两个传统金属-介质-金属（MDM）波导之间的基于表面等离子体激元的金属-介质-金属（MDM）波导慢光系统组成。我们首先考虑一个具有小宽度结构的MDM波导用于比较，然后考虑两种基于MDM波导的慢光系统：一个与短截线谐振器阵列侧耦合的MDM波导系统和一个与双短截线谐振器阵列侧耦合的MDM波导系统。我们发现，随着群速度降低，波导模式的有效折射率对填充传感器的流体折射率变化的灵敏度以及波导模式的反射和传输系数的灵敏度都会增加。对基于慢光波导的传感器结构的传感特性进行了系统分析。我们表明，与使用具有小宽度结构的MDM波导的传感器相比，慢光增强型传感器不仅使折射率灵敏度提高了3.9倍和3.5倍，从而使最小可检测折射率变化提高，而且所需的传感长度分别减少了2倍和3倍。
