Abstract
We present a semi-analytical model of the resonance phenomena occurring in a hybrid system made of a 1D array of periodic subwavelength slits deposited on an insulator/graphene layer. We show that the spectral response of this hybrid system can be fully explained by a simple semi-analytical model based on weak and strong couplings between two elementary sub-systems. The first elementary sub-system consists of a 1D array of periodic subwavelength slits viewed as a homogeneous medium. In this medium lives a metal-insulator-metal lattice mode interacting with surface and cavity plasmon modes. A weak coupling with surface plasmon modes on both faces of the perforated metal film leads to a broadband spectrum while a strong coupling between this first sub-system and a second one made of a graphene-insulator-metal gap leads to a narrow band spectrum. We provide a semi-analytical model based on these two interactions thus allowing efficient access of the full spectrum of the hybrid system.
Highlights
Extraordinary optical transmission (EOT) [1] through an opaque metallic film perforated with subwavelength slits has received great interest over the past decade because of its numerous applications in optoelectronics such as mid-infrared spatial light modulators, linear signal processing or biosensing
In particular in [19], the authors presented an electrically tunable hybrid graphene-gold Fano resonator which consists of a square graphene patch and a square gold frame. They showed that the destructive interference between the narrow- and broadband dipolar surface plasmons, which are induced respectively on the surfaces of the graphene patch and the gold frame, leads to the plasmonic equivalent of electromagnetically induced transparency (EIT)
We consider a hybrid structure that consists of a 1D array of periodic subwavelength slits ended by a metal/insulator/graphene gap
Summary
Extraordinary optical transmission (EOT) [1] through an opaque metallic film perforated with subwavelength slits has received great interest over the past decade because of its numerous applications in optoelectronics such as mid-infrared spatial light modulators, linear signal processing or biosensing. Thanks to its extraordinary electronic and optical properties, graphene, a single layer of arranged carbon atoms has attracted much attention in the last years This material can support both TE an TM surface plasmons and can exhibit some remarkable properties such as flexible wide band tunability that can be exploited to build new plasmonic devices. In [22] Zhao et al studied a tunable plasmon-induced-transparency effect in a grating-coupled double-layer graphene hybrid system at far-infrared frequencies. They used a diffractive grating to couple a normal incident wave and plasmonic modes living in a system of two graphene-films separated by a spacer. We provide analytical expressions of the reflection and transmission coefficients of the structure and describe the mechanisms leading to Lorentz and Fano resonances occurring in it
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