High Performance Broadband Asymmetric Polarization Conversion Due to Polarization-dependent Reflection

We present the underlying theory, the design specifications, and the simulated demonstration of a high performance broadband asymmetric polarization conversion composed of an L-shaped gold particle and a gold nanoantenna array for the near-infrared regime. It can transform linearly polarized light to its cross polarization in the transmission mode for one propagation direction and efficiently reflect the light for the opposite propagation direction. The broadband asymmetric polarization conversion can be attributed to the polarization-dependent reflection of the nanoantenna array, which enhances the polarization conversion efficiency of the L-shaped particle and makes it asymmetric and devisable. This work offers a further step in the development of a high efficiency broadband optical activity device.