Phys.org May 17, 2023
Despite recent demonstrations of various topological photonic phases, the full potential offered by Dirac photonic systems, specifically their ability to emulate the spin degree of freedom—referred to as pseudo-spin—beyond topological boundary modes has remained underexplored. An international team of researcher (USA – City College of New York, AFRL (Eglin AFB), Australia) showed an example of relativistic-like trapping in photonic system that realizes Dirac-like dispersion with spatially inhomogeneous mass term. The modes trapped by such cavities, their energy levels, and corresponding orbitals were characterized through optical imaging in real and momentum space. The fabricated cavities hosted a hierarchy of photonic modes with distinct radiation profiles directly analogous to various atomic orbitals endowed with unique characteristics, such as pseudo-particle-hall symmetry and spin degeneracy, and they carried topological charge which gave rise to radiative profiles with angular momentum. They demonstrated that these modes could be directionally excited by pseudo-spin–polarized boundary states. According to the researchers, in addition to the fundamental interest in the structure of these pseudo-relativistic orbitals, the proposed system offers a route for designing new types of nanophotonic devices, spin-full resonators and topological light sources compatible with integrated photonics platforms… read more. TECHNICAL ARTICLE  1 , Open Access 2
…a prototype of silicon photonic chip with information encoded in the spinning structure of optical modes. Credit: Dr. Svetlana Kiriushechkina.