Theoretical Study of Flexible Guided Mode Resonance Formed by Embedding Silver Nanoparticles in the Polymer Matrix for Strain Sensing Applications

Abstract

This paper presents a theoretical analysis of flexible guided mode resonance (GMR) structure with a configuration of an enhanced refractive index polymer nanocomposite with silver nanoparticles coated on top of a casted or imprinted grating made of the original polymer. Controlling both the volume fraction of the embedded nanoparticles (NPs) and the film thickness tunes the device sensitivity for application in mechanical lateral strain detection. The work introduces the use of the scattering matrix method (SMM) with a modification in the effective index to accurately predict the resonance wavelength peak. The results show a good agreement with rigorous coupled waves analysis (RCWA) particularly for the phase matching condition between the fundamental guided mode and diffraction. The sensitivity is calculated by perturbing the grating period due to lateral strain and correlating it to the produced wavelength shift. Using SMM for resonance wavelength calculation reduces the computational cost by a factor of 144 times while keeping a good agreement with both RCWA and the finite difference frequency domain method (FDFDM).