Tunable plasmonic perfect absorbers for enhanced biosensing and environmental detection

This study investigates arrayed split-ring nanostructures within a semiconductor-metal-semiconductor (SMS) configuration, achieving an impressive peak light absorption of 99.9 % in the near-infrared (NIR) spectrum. This high absorption efficiency is primarily attributed to Fabry-Pérot cavity resonance, which enables strong coupling of magnetic and electric fields within the structure. The resonant peak can be precisely tailored by altering the geometric parameters of the split rings, including thickness, periodicity, and other structural features, offering significant flexibility for device optimization. Compared to conventional metal-insulator-metal (MIM) setups, the SMS configuration not only delivers comparable performance but also provides a cost-effective and scalable alternative for practical applications. The design demonstrates robust sensing capabilities, achieving a sensitivity of 1000 nm/RIU in the visible spectrum and 553.57 nm/RIU in the NIR region. These characteristics highlight the potential of the proposed structure for advanced applications in photonic devices, including light-harvesting systems and highly sensitive optical sensors.