Enhancing Solar Energy Conversion in Current PV and PVT Technologies Through the Use of Metasurface Beam Splitters: A Brief Review

Metasurfaces have attracted significant interest due to their compact, artificial interfaces with exceptional optical properties. Dielectric platforms, in particular, hold promise for nonlinear nanophotonics, enabling applications such as ultrafast optical switching and high harmonic generation, which are central to developing nonlinear metaoptics. While most research has focused on single metasurfaces, stacking optical metasurfaces is a long-term goal, although it presents substantial fabrication challenges. Pancharatnam-Berry (PB) phase-based metasurfaces provide efficient wavefront control but typically require precise polarization management. These metasurfaces are particularly valuable for manipulating circularly polarized (CP) electromagnetic waves, with applications in chiral molecule interactions and optical communication. However, traditional materials-based devices suffer from bulkiness and low efficiency. PB metasurfaces, which efficiently control CP waves across different frequency domains, are becoming increasingly important. This review covers their working principles, methods for constructing high-efficiency PB metasurfaces in both reflection and transmission geometries, and their applications in meta-lensing, meta-holography, and surface coupling, concluding with perspectives on their future development. The photonic spin Hall effect (SHE), arising from the spin–orbit interaction of photons, can be precisely controlled using metasurfaces. These devices manipulate the SHE, which results in spin-dependent splitting in both position and momentum space. Integrating PB phases through space-variant polarization manipulations in metasurfaces provides new methods for fabricating spin-Hall devices. This review highlights the role of photonic SHE in metasurfaces and explores the prospects it offers for advancing spin photonics.