Efficient manipulation of plasmonic modes in single symmetry-breaking Ag nanocube

Abstract

Efficiently manipulating plasmonic modes by adjusting geometry, spatial arrangement, and the nature of the material has shown great potential in wide applications including ultrasensitive sensing, optical modulation, and surface-enhanced spectroscopy. Symmetry breaking as an effective geometry-controlled method can induce plasmonic hybridization and further tune resonant wavelength, strength, and electromagnetic fields. Herein, through introducing cavity along the cubic lateral edges, we theoretically design symmetry-breaking Ag nanocube that is capable of arbitrarily tuning plasmonic modes based on plasmon hybridization theory. Originated from the hybridization of the nanocube and cavity, bonding and anti-bonding dipole–dipole coupled modes simultaneously exhibit trends of blueshifts and redshifts by decreasing the overlapped domain and by increasing the radius of cavity. Moreover, the hybrid modes can be independently tuned by changing the edge length of the cube and the number and the location of cavity. These findings not only advance the understanding of the mechanism of light-matter interactions in symmetry-breaking Ag nanocube but also provide further guidance for designing efficient nanophotonic platforms in plasmon-enhanced spectroscopy and optical wave manipulations.