A resistive switch with optically readable and electrically writable capabilities is proposed in an engineered configuration consisting of multi-tapered and ring structures of Cu-TiO2 on silicon. The device leverages the multifunctional properties of TiO2 to enable low-voltage operation, a high extinction ratio (ER), and enhanced endurance with sensing capability. Incorporating multiple tapered regions with rings in a hybrid plasmonic waveguide enables areas with varying densities of conduction filaments in the light propagation direction. The tapered sections enhance, while the rings mitigate, light-filament interaction. The desired device functionalities are achieved with a combination of tapering and rings by modulating the interaction between a light-metal/oxygen vacancy filament. Well-defined hysteresis curves at 1550 nm prove optical readout of electrically written states in 10 nm thin TiO2. An optical ER of 20 dB is reported for a 10 μm long device. Furthermore, it demonstrates an intrinsic stochastic property that lowers the set voltage in each set-reset sweep. In addition, the UV application on the device further lowers the set voltage. The lowered set voltage across multiple cycles preserves hysteresis and ensures high endurance. Additionally, the proposed device demonstrates CO2 sensing based on the resistive switching phenomenon. Sensing capability, a high ER, and low voltage operation of the presented device pave the way for ultra-compact on-chip devices for optical switching and neuromorphic computing.
Tunable metasurfaces have attracted considerable attention for dynamic wavefront manipulation because of their capability to integrate multiple electromagnetic functions into compact devices. However, the integration of spin-decoupled dual-channel holography and electromagnetic absorption within a single metasurface platform has received limited attention. Such a metasurface provides a promising platform for applications in optical encryption, holographic displays, and sensor systems. In this work, we propose a multifunctional spin-decoupled metasurface by incorporating vanadium dioxide (VO₂) and graphene, allowing transition between dual-channel holographic imaging and polarization-insensitive perfect absorption. When VO₂ is in the metallic phase, the metasurface functions as a spin-decoupled dual-channel hologram. The proposed metasurface exhibits high robustness for dual-channel holographic imaging over the operating frequency range, with average imaging efficiencies exceeding 76% for both channels. When VO₂ transitions to the insulating phase, the holographic response is suppressed, while the graphene layer dominates the electromagnetic response, resulting in polarization-insensitive perfect absorption from 0.6 to 1 THz. The proposed metasurface provides a simple and compact platform for integrating dynamic holographic imaging and electromagnetic absorption, offering potential applications in information encryption, optical storage, and multifunctional terahertz devices.
