Enhanced Plasmon-Induced Transparency for Slow-Light Applications in an Ingenious Architecture of Asymmetrical Square Ring Resonators Integrated with Optical Switching and its high effect on the performance of a proposed index sensor and all optical logical Gates

This Study proposes an asymmetrically coupled square ring resonator coupled to a metal-insulator metal waveguide to optimize slow-light manipulation and refractive index sensing based on plasmon-induced transparency. The asymmetrical design facilitates differential excitation of the incoming light and the induced plasmons and thus interference patterns, which are responsible for power enhancement in certain input ports while blocking others. This mechanism gives higher delay times and pronounced slow-light effects. This, in turn, has greatly enhanced the sensitivity and figures of merit compared to the symmetrical structure, which suffers from lower delay times that reduce sensitivity. Such a dynamical process may result in different output modes with distinct resonator wavelengths depending on the size and propagation delays. 3D FDTD simulations indicate significant sensitivity enhancement with FOMs of 1900, 2000, 1600, and 1600 for the different modes featuring an ng of 95 and a corresponding delay of 34. These results further pinpoint the capabilities of the asymmetrical structure to work as a versatile sensor and optical switch, opening new ways toward ultra-compact devices for biomedical sensing, environmental monitoring, and high-speed communications. The multi-mode features of the output slow light system which originated from Asymmetrical SRRs lead to its tunability to be adjusted in any wavelength of interest in which specific modes have specified delay time, group index, FOM, sensitivity, and phase shift, which can be chosen from a wide range of 200 to 2000 nm included telecommunication band, moreover in this study reaching to negative delay time which originates from negative group velocity (Index) cause to the phase velocity of the SPPs waves can exceed the speed of light in vacuum, leading to unusual propagation characteristic in one hand and Superluminal Propagation in another hand enrich its performance and FOM in terms of optical switching and high modulation speed. The proposed structure presents a groundbreaking advancement in the fields of optical encoders, logically integrated circuits, and optical computing, opening new possibilities for enhanced functionality and innovation.