Exfoliated Flexible Photonic Crystal Slabs for Refractive Index and Biomolecular Sensing

Using the optical transduction properties of one-dimensional photonic crystal slabs is a promising approach for label-free biosensing in the field of flexible and wearable biosensing. In this work we demonstrate the fabrication of flexible photonic crystal slabs (f-PCS) via an exfoliation method from rigid photonic crystal slabs. We investigate the processing effect on the optical properties and show that the optical resonances are maintained, but affected. The quality factor changes from 50 to 31 for the TE mode and from 187 to 136 for the TM mode after the process. We demonstrate use of f-PCS for refractive index sensing and achieve a limit of detection (LOD) of 3.6 E-4 refractive index units (RIU). Furthermore, we introduce vapor-phase functionalization of the f-PCS and show first results of biosensing of antibodies from diluted feline serum.