Surface phonon resonance enhanced Goos-Hänchen shift and its sensing application in the mid-infrared region

The effect of surface phonon resonance (SPhR) and long range SPhR (LRSPhR) on the Goos-Hänchen shift (GHS) in the mid-infrared wavelength region are investigated. The GHS is significantly enhanced around the resonant angles of SPhR and LRSPhR with the p-polarized incident light. A highly sensitive refractive index sensor based on the enhanced GHS is proposed. The LRSPhR shows higher GHS and sensitivity than those of SPhR. The GHS and refractive index sensitivity can be further enhanced by engineering the damping rate of the phononic material. These results provide a potential route toward the large GHS and high refractive index sensitivity, thus opening up new opportunities for high sensitivity optical sensors based on GHS at the mid-infrared wavelength range.