Ultracompact Metasurface for Simultaneous Detection of Polarization State and Orbital Angular Momentum

In the field of optical communications and quantum informatics, polarization and orbital angular momentum (OAM) offer a promising way to expand the dimension of information. However, detecting the polarization state and topological charge of the OAM beam on-chip way can be challenging. To address this, an ultracompact metasurface is proposed and demonstrated. The metasurface is composed of six polarization-sensitive metalenses that occupy 60 degrees annular sectors each and are capable of simultaneous polarization state and orbital angular momentum detection. The metasurface focuses the coaxial polarized vortex beam into six locations, and the foci displacement is related to the value of the topological charge. The corresponding polarization state can be obtained through the reconstructed Stokes parameter using the six focus light intensities. For proof-of-concept, an ultracompact metasurface operating at a wavelength of 1064 nm is fabricated, which exhibits exceptional polarization and orbital angular momentum recognition ability. The proposed metasurface possesses the merits of ultra-compact size and simultaneously entire polarization state and orbital angular momentum identification capability, which may encourage the development of on-chip optical communication systems. Considering the high desire to identify both full polarization and OAM eigenstates, an ultracompact metasurface consisting of six polarization-sensitive metalens, each of which occupies a 60 degrees annular sector, is designed. The metasurface possesses the merits of ultra-compact size and simultaneously full polarization state and orbital angular momentum identification capability, which may encourage the development of on-chip optical communication systems.image