Here, we present an electrically tunable metasurface based on indium tin oxide (ITO) that enables dynamic manipulation of light wavefronts at a theoretical frequency range of 15 to 400 GHz. This all-solid-state spatial light modulator (SLM) modulates both the phase and amplitude of incoming light around the 1550 nm wavelength by utilizing an ITO layer and a periodic metallic grating structure separated by a thin AL2O3 capacitive layer. When a voltage is applied, a charge accumulation layer forms in the ITO and the ITO-oxide interface, effectively modulating the complex refractive index of the ITO. The optical transparency of the ITO layer at 1550 nm surpasses conventional reflected SLM designs, making it suitable for seamless integration with Vertical-Cavity Surface-Emitting Lasers (VCSELs), potentially reducing power consumption, heat generation, and increasing modulation bandwidth. Furthermore, the compact design and simple fabrication process allow easy integration into Photonic Integrated Circuits (PICs) as an on-chip laser source with dynamic beam steering capabilities. This unique set of properties opens up possibilities for advanced applications in on-chip computing, optical communication, environmental sensing, health diagnostics, and the development of next-generation optical computing architectures and neuromorphic computing systems.
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