Electrically Tunable Meta-Waveplate Enabled by Sb₂Se₃-Heterogeneously Integrated Piezoelectric MEMS Mirror

Metasurfaces have emerged as a powerful platform for subwavelength light manipulation, attracting widespread interest for their potential to replace bulky optical components. However, most metasurfaces are statically designed with fixed functionalities. Here, we demonstrate a high-efficiency tunable meta-waveplate by heterogeneously integrating a phase-change Sb₂Se₃ layer with a piezoelectric MEMS mirror. Leveraging the reversible amorphous-crystalline transition of Sb₂Se₃, combined with MEMS-enabled nanoscale air gap tuning, the metasurface achieves dynamic switching among zero-, half-, and quarter-waveplate functionalities at the communication wavelength of 1550 nm. The device exhibits stable polarization conversion performance under various rotation angles. Furthermore, we developed a nano-quarter-waveplate library on this platform, which provides extensive phase control over the reflected field and enables programmable beam deflection. This tunable architecture opens new avenues for adaptive photonics with dynamically switchable functionalities.