Photonic-grating-enabled selective manipulation of surface waves within the Reststrahlen band

Abstract Due to the favorable ability of strong field confinement and long lifetimes, mid-infrared (MIR) surface phonon polariton (SPhP) resonances hold great promise for advanced nanophotonic applications. Here, we report an approach to manipulate phononic surface waves by constructing a germanium (Ge) grating on a bulk polar silicon carbide (SiC) surface. The fabricated samples are characterized via the polarization- and angle-dependent reflection spectroscopy, and the experimental results reveal that the grating coupling to SPhPs takes place within the SiC Reststrahlen band, which is dominated by the depth and period of gratings. This work not only provides a better understanding for grating coupling to SPhP, but also enables potential applications in developing photonic-phononic hybrid structures with other polar dielectrics operating at Reststrahlen band.