Tunable Janus absorptive frequency-selective reflector with octave frequency absorption

A tunable Janus absorptive frequency-selective reflector (AFSR) utilizing a graphene-based hyperbolic that show-cases exceptional doubling octave frequency absorption (DOFA) or tripling octave frequency absorption (TOFA) is proposed. The multi-objective gray wolf optimization algo-rithm is employed to drive the transfer matrix method, optimizing parameters such as the dielectric permittivity, thickness, and the Fermi level (Ef) to achieve harmonic absorption. By manipulating the Ef of graphene, the dimen-sions of the absorption band and reflection window can be finely adjusted. Additionally, a frequency-selective reflec-tor is introduced, enabling a seamless transition between selective absorption and transmission by adjusting the Ef. This AFSR represents a groundbreaking approach to achiev-ing DOFA or TOFA while simultaneously offering valuable insights into the design of intelligent AFSRs.& COPY; 2023 Optica Publishing Group