Multi-frequency and multi-functional optical switch based on dual plasmon-induced transparency

Abstract Research into multi-frequency and multi-functional optical switches for complex applications is pioneering territory. By employing a single-layer structure comprising three distinct graphene strips, we successfully created a dual-PIT effect through the destructive interference among two bright modes and a dark mode. The numerical simulations were corroborated by coupled mode theory, reflecting a high degree of consistency between the theory and the simulations. Remarkably, the modulation of the Fermi level in graphene metamaterials through gate voltage enabled the realization of asynchronous optical switches capable of operating at six, five, four, and three frequencies. Notably, the six-frequency switch exhibited an impressive modulation depth of 88.54% and an insertion loss of just 0.15 dB, highlighting its superior performance. This study lays a solid foundation for future multi-frequency and multi-functional optical switch designs, offering significant implications and practical applications.