Method of Modeling of Asymmetric Resonances in Spectra of Multimode Planar Structures Based on Transfer Matrix Method

Multimode plasmonic layered structures, whose elements support the excitation and coupling of particular plasmonic modes, exhibit asymmetric resonances in angular spectra of transmission or reflection. Conventional transfer matrix method is used to describe the field amplitudes for fixed spectral parameters in such planar layer systems; however, this approach does not reveal the nature of the arising resonances. In the present work, a new mathematical method based on the transfer matrix method has been developed. This method is capable of the derivation of analytical expressions in the form of Fano-like formulas that approximate asymmetric resonances in the spectra as a result of interference between resonance and non-resonance components. Using the developed method analytical expressions for Fano parameters were obtained.