Abstract
Tunable metamaterials unfolded new scopes for active control of light absorption by engineering meta-atoms. In this study, for the first time, we propose a broadband electrically-tunable metamaterial absorber that can simultaneously modulate reflected light amplitude in both the key telecommunication wavelength bands, i.e., O-band and C-band. We leverage gap plasmon resonance (GPR) of a metal–insulator–metal (MIM) structure and epsilon-near-zero (ENZ) phenomenon of indium-tin-oxide (ITO) to enable real-time control of reflected light amplitude. The proposed metamaterial consists of an array of Au-nanograting on top of Al2O3–ITO–SiO2–Au stack. The coupling of GPR-mode with ENZ-mode is observed when an external bias-voltage is applied to accumulate free-carriers at Al2O3–ITO interface. This results in a broadening of resonance with more than 80 % absorption over a 370 nm spectral window ranging from 1.25 μm to 1.62 μm. Such dynamic control of absorption properties is then utilized for amplitude modulation of the reflected light. We achieved amplitude modulation with an extinction ratio as high as 20.5 dB and 16.7 dB at 1.55 μm and 1.31 μm of wavelength, respectively, while switching between 0 V and 5 V biasing conditions. Thus, the tunable metamaterial absorber could help realizing optical modulators operating at different wavelength bands for integrated nanophotonic systems.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call