Multifunctional Beam Manipulation at Telecommunication Wavelengths Enabled by an All‐Dielectric Metasurface Doublet

Abstract Multifunctional metasurfaces, which are planar devices featuring diverse functionalities, have attracted tremendous attention as they enable highly dense integration and miniaturization of photonic devices. Previous approaches based on spatial/spectral multiplexing of meta‐atoms on single metasurfaces are supposed to be inevitably limited in their functional diversity. An additional degree of freedom for design, achieved by cascading multiple metasurfaces into a single metasystem, promotes new combinations of functions that cannot be achieved with single‐layered metasurfaces. In this study, an all‐dielectric metasurface doublet (MD) is developed and implemented by vertically concatenating two arrays of rectangular nanoresonators on either side of a quartz substrate, in which distinct phase profiles are encoded for transverse magnetic and transverse electric polarized light. Multifunctional beam manipulation with concurrent increased beam deflection, beam reduction, and polarizing beam splitting is achieved at telecommunication wavelengths near 1550 nm. The MD is accurately created via lithographical nanofabrication, thus eliminating the extremely demanding post‐fabrication alignment. The proposed multifunctional metasurface is highly anticipated to expedite the development of advanced technologies for large‐scale photonic integration, optical metrology, light detection and ranging, spectroscopy, and optical processing.