Subwavelength Broadband Photonic Spin Hall Devices Via Optical Slot Antennas

The photonic spin Hall effect, wherein left- and right-handed circularly polarized components can be separated during transportation after reflection or refraction by an optical interface through spin-orbit interaction, has gained increasing attention from the scientific and technological fields. Here, broadband subwavelength photonic spin Hall devices (PSHDs) are demonstrated on the basis of L-shaped optical slot antennas. A basic PSHD comprises two L-shaped slot antennas with a footprint size of 300 nm x 700 nm. The angle between the two radiation directions of the incident lights with different spins varies from 56 degrees to 31 degrees in the wavelength range of 750 to 850 nm. An array of antenna pairs is used to control radiation directions and improve the performance of the PSHDs. The proposed PSHDs are highly useful in integrated nanophotonic devices given their ultrasmall size, broadband response, and flexible design method.