Optical resonant transmission in metal–dielectric multilayers

Abstract

We have investigated optical transmission due to resonant tunnelling through metal/dielectric multilayers using the tight binding model and the invariant embedding method. The tight binding model for the resonant modes in metal/dielectric multilayers describes well the splitting of resonant modes and can predict the frequencies of split resonant modes in the transmission spectra of the metal/dielectric multilayers. We also show that the transmittance of a metal/dielectric multilayer increases as the thickness of the outer metal layers decreases with the total metal thickness kept constant. This is because the transmission of resonant modes increases as the thickness of the outer metal layers decreases. The thickness of the outer metal layers is found to change not only the transmittance but also the resonant transmission peak positions. When the thickness of each dielectric layer is fixed, the bandwidth of the transmission spectrum is mainly affected by the thickness of the metal layers inserted between the dielectric layers since this thickness determines the coupling strength between the resonant modes.