Nonlocal effect on transverse-magnetic photonic properties of periodic dielectric-metal stacks

We study scattering of a transverse-magnetic electromagnetic wave by a stack of thin metal layers with the width comparable to the skin-depth of the electromagnetic field in bulk metal. We use a microscopic approach based on the Boltzmann kinetic equation, which makes it possible to describe not only the nonlocality of metal conductivity but also the diffuse interaction of charge carriers with the surfaces of the metal film. Solving the Maxwell equations with nonlocal current density, we compare the transmittance, reflectance, and absorption of a stack with those originated from the local approximation based on the Drude model, which describes neither nonlocality of metal conductivity nor diffuse surface scattering of electrons. Although it is considered that nonlocal effects are relevant only within the microwave frequency range at helium temperatures, we show that at room temperatures, the infrared transmittance, reflectance, and absorption of a dielectric-metal stack can also differ substantially from the corresponding values predicted by the local approximation.