Guided-mode resonance photonic crystal slab sensors based on bead monolayer geometry

Using finite-difference time-domain method, we investigate photonic crystal slabs consisting of spherical voids or silica beads embedded into a dielectric slab as bio-chemical sensors. We study the dependence of the spectral position of guided-mode resonances on the refractive index of a slab material. The most sensitive design is based on voids filled with analyte. We also study the effects of the slab and analyte thicknesses on guided-mode resonance properties. We eventually demonstrate an aqueous analyte sensor with high sensitivity at visible wavelength as electro-magnetic energy distribution in some guided-mode resonances can be strongly localized in the analyte region.