Topological Sensing with Photonic Arrays of Resonant Circular Waveguides*

We propose a topological framework for robust chemical detection based on a photonic array of circular dielectric waveguides with a subwavelength grating structure. We show that the device can be designed to create a chemically-sensitive photonic edge mode which is impervious to most sources of disorder. By performing realistic simulations of such a device in the mid-infrared regime that includes absorption loss introduced by the chemical species, we were able to demonstrate the viability of the proposed sensor for applications in trace gas detection capable of reaching the pars-per-billion range at the millimeter scale. These findings suggest that chemical sensors based on topological photonic designs could provide a new pathway for the development of novel on-chip integrated photonic sensing technologies.