The simultaneous processing of orbital angular momentum (OAM) and polarization\nhas recently acquired particular importance and interest in a wide range of fields ranging\nfrom telecommunications to high-dimensional quantum cryptography. Due to their inherently\npolarization-sensitive optical behavior, Pancharatnam-Berry optical elements (PBOEs), acting on\nthe geometric phase, have proven to be useful for the manipulation of complex light beams with\northogonal polarization states using a single optical element. In this work, different PBOEs have\nbeen computed, realized, and optically analyzed for the sorting of beams with orthogonal OAM\nand polarization states at the telecom wavelength of 1310 nm. The geometric-phase control is\nobtained by inducing a spatially-dependent form birefringence on a silicon substrate, patterned\nwith properly-oriented subwavelength gratings. The digital grating structure is generated with\nhigh-resolution electron beam lithography on a resist mask and transferred to the silicon substrate\nusing inductively coupled plasma-reactive ion etching. The optical characterization of the fabricated\nsamples confirms the expected capability to detect circularly-polarized optical vortices with different\nhandedness and orbital angular momentum.
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