We study the cooperative effects between plasmon gap modes and optical cavity modes of a novel triple-layer structure consisting of double continuous gold films separated by a gold nanosphere array. Narrowband near-perfect antireflection of optical field is achieved for the first time due to the strong near-field light–matter interaction within the deep sub-wavelength gaps between adjacent nanospheres combined with the spatial field confinement effects of the optical cavity built by the double gold films. The coexistence cooperation of near-field dipole plasmon resonances and spatial optical field confinement presents more efficient light modification than that of the individual subsystem and may open a new approach to manage light flow. By varying the period of nanosphere array, the diameter of nanospheres, and the distance between the array and the film, optical behaviors of the proposed structure can be tuned in a wide range. High environmental sensitivity and large figure of merit factor are obtained using this structure as the detecting substrate. Furthermore, ultra-compact structure and high conduction suggest the proposed structure being a good candidate for potential applications in highly integrated optoelectronic devices, such as plasmonic filters and sensors. 相似文献
The optical properties of a novel nanostructure consisting of a hexagonal array of aligned vertically three-layered metal-dielectric-metal nanodisks on a silver film are theoretically studied through the finite-difference time-domain method. The novel nanostructure exhibits three obvious optical transmission bands due to the excitation of subradiant plasmon modes, superradiant plasmon modes, and Fano resonances. Surface plasmon polaritons of the underlying Ag film also play a significant role on these three optical transmission bands via coupling with localized surface plasmons of nanodisk pairs. Moreover, the nanostructure also exhibits a good tunability of optical response by modifying the sizes of cylinders, the thickness of underlying metal film, and the dielectric constant of middle layer. These results demonstrate the nanostructure with great advantages in optical sensors and filters.