Optimally designed narrowband guided-mode resonance transmittance filters for label-free optical biosensor

We design a practical guided-mode resonance filter excited in the visible light region. We show that high background transmission over 90% at resonance wavelengths of 623 nm and 641 nm for TE and TM polarizations, respectively. Also, we investigate the sensitivity of the filter to incident angles, polarization and the refractive index of the surrounding environment. Our filter provides the resonant transmission spectral response with high sensitivities of 90 nm/RIU and 103 nm/RIU, and with a figure of merits of 1.93 and 2.13 for TM and TE polarizations, respectively. A GMR with such characteristics is expected to hold great promise a practical label-free refractive index biosensor.