Polarization Detection of Terahertz Waves using All‐Silicon Metasurfaces with Tightly Focusing Behavior

Abstract

The manipulation of polarization states is reflected in the tailoring of light–matter interactions and has great applications in fundamental science. Nevertheless, the conventional polarization‐separated detection behavior in the terahertz (THz) band is very challenging when applied to visualize the incident polarization state since its measurement requires sophisticated instrumentation. Here, the feasibility of its reconstruction of the full‐Stokes parameter matrix in the THz band is explored by establishing an all‐silicon decoupled metasurface based on the polarization multiplexing encoding technique. The pixelated focal spots gathered in the target plane allow us to employ more elaborate methods to extract the characteristic parameters of the incident polarization states. The resolvability of the THz polarization detection behavior with a single focal spot is further optimized benefiting from the longitudinal polarization component (Ez) generated by the tightly focused beam in the propagation direction. The capability of the Ez‐component in determining the key parameters that compose the polarization ellipse is evaluated by predefining the random incident polarization on a standard Poincaré sphere. Thus, the proposed scheme offers significant advantages in future THz communications, providing opportunities for ultra‐compact, high‐resolution full‐Stokes polarization imaging and multidimensional information processing.

Terahertz bi-functional polarization converter based on interference mechanism supported by diatomic metasurfaces

“…xx +t 2 yy calculated for the QWP array under x-polarized illumination [39]. Obviously, the value of the S 3 parameter calculated in the broadband range is close to 1, indicating that the incident x-polarization will be further converted to LCP.…”

All-dielectric terahertz metasurfaces for arbitrary linear polarization detection

“…As for experiments, the polarization behavior can be evaluated using the TeraCube Scientific M2 THz near-field detection system. The system is equipped with a TeraSpike TD-1550-X probe that captures complex amplitude information directly at the focal plane [31].…”

“…A generalized design scheme for generating VBs via all-dielectric metasurfaces has applications in various fundamental fields, including optical communications [27], optical trapping [28], and quantum optics [29]. As a promising candidate, two VBs with the same intensity distribution but opposite topological charges interfere with each other in the appropriate polarization direction to generate the focused vector vortex fields [30][31][32]. Theoretically, different OAM modes are orthogonal to each other, and an infinite variety of values can significantly increase the communication capacity.…”

Wide-angle metalens array with quadratic phase for terahertz polarization detection

“…Terahertz wave is located between the microwave and infrared, accurate measurement of SOP of terahertz wave can contribute to the research of magneto-optical effect, material properties and chiral molecular/metamaterial identification [47,48]. There have been several endeavors to be devoted to the metasurface-based polarimeter in the terahertz region [49,50], but most of them only consider normally incident terahertz wave. In this paper, a dielectric wide-angle metalens array (WMA) for the terahertz polarization detection is proposed and demonstrated.…”