Abstract
Designing powerful electromagnetic wave modulators is required for the advancement of optical communication technology. In this work, we study how to efficiently modulate the amplitude of electromagnetic waves in near-infrared region, by the interactions between the interband transition of graphene and the magnetic dipole resonance in metamaterials. The reflection spectra of metamaterials could be significantly reduced in the wavelength range below the interband transition, because the enhanced electromagnetic fields from the magnetic dipole resonance greatly increase the light absorption in graphene. The maximum modulation depth of reflection spectra can reach to about 40% near the resonance wavelength of magnetic dipole, for the interband transition to approach the magnetic dipole resonance, when an external voltage is applied to change the Fermi energy of graphene.
Highlights
Controlling the spectral properties of electromagnetic waves by external stimuli such as mechanical force, temperature change, electrical voltage, and laser beam [1–4] has been drawing increasing interest, because of many applications in the fields of holographic display technology, highperformance sensing, and optical communications
It is found that the reflection spectra of metamaterials can be largely reduced in the wavelength range below the interband transition of graphene, because the enhanced electromagnetic fields from the magnetic dipole resonance greatly increase the light absorption in graphene
The modulation depth is generally defined as (R-R0)/R0, where R and R0 are the reflection spectra with and without graphene inserted in metamaterials [34]
Summary
Controlling the spectral properties of electromagnetic waves by external stimuli such as mechanical force, temperature change, electrical voltage, and laser beam [1–4] has been drawing increasing interest, because of many applications in the fields of holographic display technology, highperformance sensing, and optical communications. In the past few years, much effort has been made to actively manipulate the transmission, reflection, or absorption spectra of electromagnetic waves, which is based on electrically tunable surface conductivity of graphene, in a very wide frequency range including microwave [5, 6], terahertz (THz) [7–33], infrared [34–65], and visible regime [66–69]. At higher frequencies, graphene itself no longer supports surface plasmon resonances, but behaves more like an ultra-thin dielectric film when it interacts with light In this situation, various high-quality resonance modes supported in other nanostructured materials are often explored to electrically modulate electromagnetic waves, with the help of the gate-controlled Fermi energy of graphene. Up to now, there are only a few studies on optical modulators that are based on magnetic resonance in metamaterials with an inserted graphene monolayer [34]
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