Abstract
The visible and ultraviolet responses of a binary regular stack, composed of alternating Al and Ag nano-thin layers, are both experimentally and theoretically studied. It is found that the s- and p-polarization reflectivity spectra (Rs and Rp, respectively) of the inherently anisotropic bimetallic system are noticeably different due to the appearance of a prominent dip near the zero of the Ag permittivity. Such an effect is similar to the Berreman one, which is observed in thin polar-crystals films near the longitudinal-optical phonon frequency, as well as in thin metal films near plasma frequency. Using both the effective medium approach and a nonlocal homogenization formalism, being valid even beyond the long wavelength limit, it is demonstrated that the bimetallic multi-layer stack behaves as a uniaxial anisotropic metamaterial. As it is shown, the appearance of the dip in the p-polarization spectrum is associated to the zero of the longitudinal component of the effective permittivity (ϵz). The calculation of 45-degree reflectometry spectrum, namely the difference Rp−Rs2, from experimental and theoretical reflectivity data confirmed that the observed dip in Rp is connected to a plasma resonance of the energy-loss function ℑ(−1∕ϵz).
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
