Dynamic dual-functional optical wave plate based on phase-change meta-molecules

Optical metasurfaces have shown great potential for revolutionizing wave plates by enabling compact footprints and diversified functionalities. However, most metasurface wave plates (meta-WPs) are typically passive, featuring defined responses after fabrication, whereas dynamic meta-WPs have so far often been limited to ON and OFF states. Here, we design a dynamic dual-functional meta-WP based on judiciously designed low-loss Sb₂Se₃ meta-molecules at the telecom wavelength of 1.55 µm which enables reconfigurable linear-to-circular and linear-to-linear polarization conversion for orthogonal linear polarizations when Sb₂Se₃ transits between amorphous and crystalline states. In addition, a comprehensive electro-thermal simulation is carried out to verify the phase change process for realistic implementation. The designed dynamic dual-functional wave plate may open new avenues for developing integrated adaptive photonics with dynamic and multiplexed functionalities.