Aperture-layout-induced effects in polarization-resolved multifocal metalenses based on plasmonic quarter-wave plates

Polarization-resolved metasurfaces offer a compact platform for simultaneous control of wavefront and polarization; however, the role of aperture-level multiplexing in device performance remains largely unexplored. Here, we design and experimentally demonstrate two polarization-resolved multifocal metalenses based on plasmonic quarter-wave plates: a segmented metasurface and an interleaved metasurface. Under circularly polarized illumination, both devices generate four focal spots with independently prescribed linear polarization states, enabling simultaneous circular-to-linear polarization conversion and multifocal phase modulation. The two layouts are experimentally characterized and compared in terms of polarization-resolved focal-field distributions, angle-of-linear-polarization errors, and degree of linear polarization over a broadband wavelength range. These results provide practical guidelines for advanced polarization shaping and integrated flat photonic devices.