Polarization control and switchability are among the most unique features of "metasurfaces" as compared with diffractive optics technologies of the past. Here, we review how the polarization control afforded by the advent of present-day metasurfaces compares to diffractive elements of previous decades, clarifying from a functional perspective what is new, and what is not.
Keywords: diffractive optics; nanophotonics; polarization.
© 2025 the author(s), published by De Gruyter, Berlin/Boston.