Tunable dual-band polarization filter in infrared range realized by nested asymmetrical cross-shaped resonator arrays

A tunable dual-band polarization filter in infrared range has been proposed and investigated in this paper. The metal-dielectric-metal sandwich structure which possesses perfect absorption property is used to realize the filter. The calculated results show that different dual-band wavelengths of the reflection spectrum are filtered while the incident light has different polarization which is parallel or vertical to the x axis. Moreover, it is found that the filtered wavelengths (resonant wavelengths) can be tuned independently and freely by adjusting the length of the corresponding rectangular strips. 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.