2D addressable mid-infrared metasurface spatial light modulator based on nonvolatile phase change materials

Electrically reconfigurable metasurfaces enable programmable flat optics, yet scalable two-dimensional (2D) electrical addressing and transmissive mid-infrared (mid-IR) operation remain unresolved challenges. We present a foundrycompatible 2D active metasurface architecture that integrates nonvolatile phase-change materials (PCMs) with silicon microheaters, multilayer backend-of-line metal routing, and pixel-level diode selectors arranged in a crossbar configuration. The selector-integrated design suppresses sneak-path currents and enables independent pixel programming without interconnect congestion, providing a scalable pathway beyond one-dimensional fan-out schemes. Using this platform, we demonstrate the first transmissive mid-IR spatial light modulator operating at 2.585 µm, implementing a 6 × 6 pixel array with reversible optical contrast of 5.1 dB and endurance exceeding 16,000 switching cycles. Fabrication within a commercial silicon photonics foundry establishes a manufacturable route toward large-area, high-density programmable metasurfaces for infrared wavefront engineering applications.