In this work we introduce a novel and viable model for the measurement of ethanol concentration in water. The concept relies on the optical high spectral sensitivity of plasmonic devices. The ethanol in water mixture shows a linear ratio with the refractive index and the concentration percentage on a selected range of 0 to 45%. The proposed model is based on the refractive index linear relationships of the ethanol concentration and the plasmonic resonance wavelength. Therefore enabling the indirect measurement of the ethanol concentration through the plasmonic resonance wavelength.

Omnidirectional band gaps are found in a ternary structure, quarter-wave-like, dielectric-dielectric-metal. We plot the band gaps through the analytical dispersion relations, derived using the transfer matrix method, for oblique incidence (transversal electric and magnetic modes).