![]() The introduction of the symmetric broken Archimedes’ spiral geometry structure supplies the opportunity to nano-scale optical elements for sensing applications and convenient optical integration for measuring full Stokes-vectors of the polarization information. The construction of double spiral gratings with central hole dynamically switches the incident CPL into the beams with different OAMs due to the extra OAM originating from the spiral geometry structure. In addition, they can generate the optical vortex light carrying well-defined OAM. These nanostructures have distinct superiority in miniaturization and analyzing the CPL incidences with high efficiency. In this review, we firstly review several nanostructures based on Archimedes’ spiral, including the pure single-turn Archimedes’ spiral slit (ASS), multiple-turn ASS, a hybrid spiral plasmonic lens, a concentric annular groove surrounded by ASS, Archimedes’ spiral gratings (ASG) combined with ASS, a metal-insulator-metal (MIM) waveguide combined with ASS, the aberrance of ASS, and so on, which can realize the functions of selecting and analyzing the polarization states of CPL incidences. These spiral structures have brought about extensive investigations for optical applications in polarization selection, polarization conversion, plasmonic focusing and selective trapping. The angular momentum of an optical beam contains the intrinsic component of the spin angular momentum (SAM), associated with the handedness of circular polarizations, and the extrinsic component of the OAM originating from the spiral phase profile of the beam around the axis of propagation. In recent years, more attention has been paid to the Archimedes’ spiral structure with regard to its functionality for circular polarization analysis and generating arbitrary orbital angular momentum (OAM) under illuminations of circular polarization light (CPL). At an early time, the Archimedes’ spiral configurations served as spiral antennas due to the broadband characteristics as circularly-polarized radiators, which can also provide a new idea for the underlying polarization-dependent effect. Such Archimedes’ spiral plasmonic structures can be used as the circular polarization analyzer for replacing a quarter wave plate combined with a linear polarizer, which will offer the possibility for potentially miniature integration. The emerged nano-scale metallic structures, which produce a strongly polarization-dependent optical response, can be a promising alternative for obtaining polarization information. However, the utilization of bulky optical devices hinders the miniaturization of integrated optical system. ![]() In contrast, it is still a challenge to directly detect and analyze the circular polarization state, where a quarter wave plate and a linear polarizer are simultaneously needed. Investigations of acquiring the linear polarization state have been performed very well from the visible to infrared range. Additionally, this property can be also employed in other applications, including optical communications, imaging polarimetry and microscopy. Polarization, as one of the basic properties of the light, is widely used in modern sensor systems, by which the important information of reflecting objects can be obtained and recognized because there are different polarization characteristics for different objects. Such functional spiral plasmonic nanostructures are promising for applications in analyzing circular polarization light, full Stokes vector polarimetric sensors, near-field imaging, and so on. The circular polarization extinction ratio, as an evaluation criterion for the polarization selectivity of a designed structure, could be effectively improved by properly modulating the parameters of spiral structures. ![]() Many investigations demonstrate that the multifunctional spiral-based plasmonic structures are excellent choices for chiral selection and generating the transmitted field with well-defined OAM. These features can be used to analyze different circular polarization states, which has been one of the rapidly developing researching topics in nanophotonics in recent years. Here, we have reviewed some typical plasmonic structures based on Archimedes’ spiral (AS) architectures, which can produce polarization-sensitive focusing phenomenon and generate plasmonic vortices (PVs) carrying controllable orbital angular momentum (OAM) because of the relation between the incident polarized states and the chiralities of the spiral structures.
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