2-bit encoding, sensing and slow light based on triple plasmonic induced transparency effect

In this study, a multifunctional device based on triple plasmonic induced transparency (PIT) is proposed. We employed coupled mode theory to derive the underlying mechanism of the triple plasmonic induced transparency phenomenon. The theoretical findings were then verified using the finite-difference time-domain simulations. The results from both approaches were found to be largely consistent. The device can realize the 2-bit coding at 29.01 and 34.74 THz by voltage. The maximum extinction ratio and modulation depth can reach 15.16 dB and 96.95%, respectively, and the minimum insertion loss can reach 0.11 dB. The device also has excellent sensing performance, with sensitivity and figure of merit of up to 4.21 THz/RIU and 112.67. In addition, the group refractive index of the device can reach 484.93 when the Fermi level of graphene is controlled to 1.00 eV. Therefore, these results reveal that our research is expected to provide a theoretical basis for potential applications such as terahertz coding, sensing, slow light, optical switching, and optical storage.