Dark plasmonic modes in diatomic gratings for plasmoelectronics

Abstract

AbstractOwing to the unique ability of nanostructured metals to confine and enhance light waves along metal‐dielectric interfaces, plasmonics has enabled unprecedented flexibility in manipulating light at the deep‐subwavelength scale. With regard to the spectral behavior of plasmonic resonances, the spectral location of a resonance can be tailored with relative ease while the control over the spectral linewidth represents a more daunting task. In this paper, we present sharp resonance features by introducing dark plasmonic modes in diatomic gratings. The induced asymmetry in the metallic structure facilitates the generation of a dark mode with significantly suppressed radiative loss leading to an ultra‐sharp spectral feature ∼5 nm wide. We further use this metallic structure as an optoelectronic platform for the transduction of light waves to electrical signals via a plasmoelectric effect. The light concentrating ability of dark plasmonic modes, in conjunction with the ultra‐sharp resonance feature at a relatively low loss offers a novel route to enhanced light‐matter interactions with high spectral sensitivity for diverse applications. image