Polarization‐Multiplexing Bessel Vortex Beams for Polarization Detection of Continuous Terahertz Waves

Abstract

Determination of polarization states of electromagnetic waves plays a crucial role in photonic applications. However, it is very challenging to determine the polarization state of continuous terahertz (THz) waves. Here, a metasurface-like metallic waveguide array (MWA) is proposed to address this by measuring both the phase difference and amplitude ratio of its two orthogonal components based on generation and interference of polarization-multiplexing vortex beams. When a full-polarized THz wave passes through the MWA, its two orthogonal components will be converted into +1 st -and −1 st -order Bessel vortex beams, respectively. Their projection components in a proper polarized direction can interfere with each other, and their initial phase difference can be measured in real-time owing to its linear relationship with the azimuth of the dark fringe in interference patterns. The two Bessel beams can be further collected separately using a linear polarizer to obtain their amplitude ratio. Therefore, the polarization state of incident waves can be determined with both the phase difference and amplitude ratio. The proposed method enables a convenient polarization determination of continuous THz waves and has great potential for developing polarization-dependent investigations and applications in THz detection, communication, and sensing.

Polarization detection for cylindrical vector beams empowered by pixelated metasurfaces

“…The corresponding engineering applications include particle trapping, high-resolution imaging, and laser processing [27][28][29]. In the terahertz (THz) band, polarization detection techniques based on separated meta-optical systems suffer from significant insertion losses, e.g., waveplates [30]. Not only that, the detection targets of the employed meta-platforms are only suitable for homogeneous polarization distributions and are not universally applicable to CVB modes carrying inhomogeneous polarization profiles [31][32][33].…”

High-efficiency polarization converter with near-unity transmittance in the visible wavelength based on all dielectric rod metasurface array

“…Effectively regulating the polarization state of light is one of the popular research topics in the field of optics, which has important applications in many fields like polarization measurement, polarization imaging, quantum communication and optical sensing [1][2][3] . Polarization manipulation could be achieved by conventional waveplates made of birefringent crystals.…”

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

“…This is because the insertion loss of conventional THz waveplates is much higher than that of optical waveplates when measuring the full‐Stokes parameters. [ 27 ] Subsequently, we modified the conventional separated polarization detection for the superiority of the THz near‐field scanning system, i.e., the full‐Stokes parameters were reconstructed using multiplexed metasurfaces with single‐point focusing characteristics. The pixelated focal spots assembled on the focal plane allow us to employ more elaborate algorithms to extract the key parameters of the incident random polarization state.…”