By introducing the sub-wavelength grating (SWG) waveguide in the long-range surface phonon resonance (LRSPhR) device, a mid-infrared Fano resonance is formed due to the coupling between surface phonon polariton and Bloch mode. By taking advantage of strong light-matter interaction in the SWG, such Fano resonance is expected to offer improved sensing performance. Based on the rigorous coupled-wave analysis (RCWA) method, the index sensitivity and figure of merit of such a sensor reach 7496 RIU⁻¹ and 46,432, respectively, which is 6 times compared with the conventional waveguide-coupled LRSPhR. The proposed SWG-coupled Fano resonance can be a promising platform for mid-infrared biochemical sensing.

通过在远程表面声子共振（LRSPhR）器件中引入亚波长光栅（SWG）波导，由于表面声子极化与Bloch模式之间的耦合，形成了中红外Fano共振。通过利用SWG中强大的光物质交互作用，这种Fano共振有望提供更高的感测性能。基于严格的耦合波分析（RCWA）方法，该传感器的折射率灵敏度和品质因数分别达到7496 RIU ^-1和46,432，是传统波导耦合LRSPhR的6倍。拟议的SWG耦合Fano共振可以成为中红外生化传感的有前途的平台。