Linear optical properties of periodic hybrid materials at oblique incidence: A numerical approach

We discuss optics of periodic hybrid systems — materials comprised of plasmon sustaining structures and molecular aggregates. The emphasis is on the linear regime under strong coupling conditions between molecules and surface plasmon-polaritons. The numerical algorithm used in this work relies on a utilization of two sub-cells to account for propagating numerical errors. With the developed numerical procedure we examine transmission properties of one-dimensional periodic diffraction gratings with sinusoidal spatial modulation. It is shown that such systems exhibit three surface plasmon-polariton resonances that split when the incident radiation is not at the normal incidence. By adding resonant molecular aggregates to such a grating and tilting the incident angle we are able to demonstrate strong coupling between molecules and surface plasmons.