Angular-selective multifunctional optical devices using graphene-embedded one-dimensional photonic crystals

The challenge of achieving effective angular selection has garnered significant research interest. In this paper, a one-dimensional photonic crystal (1DPC) containing graphene layers is proposed that enables polarization-insensitive and broadband angular selection. By utilizing the critical angle for total reflection, high-performance spatial filtering is achieved. Under transverse electric waves, total reflection occurs when the incident angle is greater than 55° while high transmission occurs when the incident angle is less than 55°. Under transvers magnetic waves, the transition angle is observed at 50°. Angular selection performance is maintained with remarkable consistency across both polarizations and remains robust across a wide bandwidth (relative bandwidth is equal to 85.7%). The slight angular discrepancy (∼5°) between transverse electric and transverse magnetic modes is exploited to create conditions conducive to the photonic spin Hall effect (PSHE), enabling significant V-component of transverse displacement that is specifically observed around 45°. By defining ambient temperature and applied voltage as inputs within an encoding scheme, and by utilizing the PSHE displacement magnitude as the output, superior angular selectivity is provided, and the optical encoding of spin information is enabled. This multifunctional optical functionality offered a novel design pathway for encoder devices, optical orientation systems, and spin-based photonics.