Enhancement of spin-orbit interaction and nearly perfect spin-reversed efficiency in a one-dimensional photonic crystal containing an anisotropic defect.

Although the defect modes of photonic crystals (PhCs) have been intensively investigated to enhance the interactions between light and special materials, e.g., nonlinear material for switches or gain material for lasers, the enhancement of photonic spin-orbit interaction (SOI) by the defect modes has not been well studied so far. In this work, based on the PhCs containing the anisotropic-material defect, we find rich and new phenomena for such systems from the enhanced SOI, such as the high vortex-conversion efficiency and saturation at 50% for the normally incident Gaussian beam, the large photonic spin Hall effect (PSHE) for obliquely incident beam beyond the Brewster angle and the nearly complete spin-reversed efficiency when we tune the different-order defect modes of s - and p - waves to coincide together. New mechanisms are also revealed, such as the very different sensitivity to the incident angle for the resonant frequencies of the defect modes of s - and p -waves, the tunable sensitivity by choosing proper cell-number N of PhCs for different designs, and the near π-phase jump between different-order defect modes. The hybrid of these new mechanisms is the novel resource of these new phenomena beyond traditional systems. Besides the theoretical importance, these new mechanisms from the defect modes of PhCs can also be widely used to design extremely compacted SOI devices, such as the vortex beam or spin-reverse generators and spin-sensitive detectors.