Multi-polarization selective absorber based on terahertz metasurface

Tunable absorbers attract much attention due to their wide applications, such as integrated optical sensors, multiplexing far-field imaging and so on. In this paper, we design a multi-polarization selective absorber based on terahertz metasurface, whose geometric symmetry is tunable to satisfy the requirements of linear and circular polarization selective absorbers. At the ON state, the metasurface selectively absorbs y-polarized wave at 1.0 THz, with the linear dichroism of 0.84. At the OFF state, the metasurface selectively absorbs left circularly polarized wave at 1.16 THz, with the circular dichroism of 0.81. The physical mechanism of the metasurface is explained by the Jones calculus and the electromagnetic field distributions. In addition, the multi-polarization selective behavior is insensitive to the incident angle. Finally, we design a sample to verify the potential application of the metasurface absorber, which displays multiplexing imaging of ‘C’, ‘mirrored C’, ‘O’ and blurred images under different polarized incidences at different states. Such a metasurface, switching between linear polarization selective absorber and circular polarization selective absorber, may achieve stable applications in multifunction integrated absorbers, detectors, and image encryptions.