Design and simulated characterization of the dual-band polarizer based on metasurface structure

Dual-band polarizers must simultaneously exhibit high transmittance and bandwidth efficiency in fields such as polarization navigation and efficient detection. However, in most studies, the detection of dual bands is inefficient. To address this issue, we designed a dual-band polarizer similar in structure to the Roman numeral II, and it allows transmission of two different linear polarizations within different frequency bands. The interaction of the dual-band nano-polarizer with the polarization state of the incident light was analyzed through simulation experiments on the material, height, duty cycle, and other parameters of the periodic structure of the polarizer unit. The simulation results show that the proposed dual-band polarizer could achieve a polarization degree above 0.75 in the visible range and above 0.8 in the near-infrared (NIR) range. In addition, the transmittance was above 80% for x-polarization light in most of the visible wavelengths and reached 97.7% for y-polarization light in the NIR region, where NIR bandwidth accounted for 83.3% of the NIR wavelengths. The proposed design can achieve high transmittance and can be applied to ultrawide single-band polarization detection or dual-band vertical polarization detection.