Active and AI-Assisted Slow-Light Engineering in Periodic MDM Waveguides

This study investigates the recent advancements in periodic metal-dielectric-metal (MDM) plasmonic waveguides that use plasmon-inductive transparency (PIT) for slow light engineering. The basic mechanism of PIT, based on the interference between bright and dark resonance modes, is discussed using time-coupled mode theory, while the role of periodicity and Bloch mode dispersion engineering in controlling group velocity, bandwidth, and group velocity dispersion is highlighted. This article traces the development of PIT-based structures from static single-unit configurations to adjustable active architectures with artificial intelligence (AI) assistance, covering studies carried out from ۲۰۱۸ to early ۲۰۲۵. Special attention has been paid to graphene-based metasurfaces, integrated devices with phase-shifting materials, and periodically reverse-designed systems, which enhance the balance between the amplification, adjustment, and dissipation of slow light. The recent studies from ۲۰۲۴ to ۲۰۲۵ indicate that molybdenum disulfide is a compatible alternative with CMOS for graphene, hybrid PIT full absorption platforms which are activated by vanadium (IV) oxide, and multi-window PIT structures with switching capabilities and robust sensors. According to the advanced graphene-based designs, group indices exceeding ۲۰۰۰, modulation depths approaching ۹۹%, refractive index sensing sensitivities up to ۱۷۷۴ nm/RIU, and terahertz-range sensitivities up to ۳.۷۴۶ THz/RIU have been reported. Overall, the convergence of periodic dispersion engineering, active materials, multi-window PIT architectures, and intelligent reverse design facilitates the transition of PIT-based slow light systems from proof-of-concept samples to high-performance, integration-ready nanophotonic platforms.

کلیدواژه ها:

Plasmon-induced transparency (PIT) ، Slow light ، Periodic MDM waveguides ، Graphene metasurfaces ، Multi-window PIT