High spatial resolution Stokes metasurface based on three-pixel technology

A dynamically reconfigurable metasurface grating is proposed in this work based on the phase change material Ge₂Sb₂Te₅ (GST). The metasurface grating keeps as the 0° polarizer that allows only x-polarized light to pass when the GST is in the crystalline state, and switches to the 90° polarizer (only y-polarized light passes through) while the GST transforms into the amorphous state. Furthermore, the circular polarization dichroism could be achieved using a double-layer metasurface consisting of this dynamic grating and a large broadband plasmonic quarter-wave plate. We can expect to achieve fully polarized detection with the ultra-high spatial resolution using only three components. In addition, we can obtain the largest bandwidth (300 nm) of the full Stokes large-image-element to date in the near infrared band by using the six-image-element technique with the crystalline phase GST.