Materials science

Physical chemistry

Polarization (electrochemistry)

Linear polarization

Laser

Physics

Microstrip

Dielectric

Optics

Terahertz radiation

Resonator

Circular polarization

Chemistry

Optoelectronics

Elliptical polarization

Optics Letters

We propose a reflective terahertz (THz) metalens with four focal points for polarization detection of THz beams. The metalens is composed of Z-shaped resonators with spatially variant orientations, a reflective gold layer, and a dielectric spacer between them. The polarization states of the focal points include left circular polarization, right circular polarization, an incident polarization state, and a polarization state whose major axis is rotated π/4 in comparison with that of the incident polarization. The handedness, ellipticity, and major axis of the polarization state can be determined based on the light intensities of the focal points. The uniqueness of the designed device renders this technique very attractive for applications in compact THz polarization detection and information processing.

Multi-foci metalens for terahertz polarization detection