Infrared tunable dual-band polarization filter based on compound asymmetrical cross-shaped resonator

We propose an infrared tunable dual-band polarization filter in this paper. Based on the perfect absorption characteristic of the metal-dielectric-metal sandwich structure, the reflection spectrum performs as a filter. The calculated results show that different dual-band wavelengths are filtered while the incident light has different polarization which is parallel or vertical to the x axis. Moreover, it is found that the resonant wavelengths can be tuned independently and freely by adjusting the length of the corresponding rectangular strip. In addition, it is found that all of the intensities at the filter wavelengths are closed to zero, which implies the filter exhibits good filtering performance.