Abstract: Orbital angular momentum (OAM) based photonics promises researchers and systems designers with a new degree of freedom whilst offering annular intensity distributions rather than Gaussian intensity distributions. However, absence of an optical fiber design that not only supports propagation of OAM signals and cylindrical vector modes but does so with a large design space for designers to adjust and tune the modal properties of the optical fiber supporting these OAM signals has hampered developments. Embodiments of the invention exploit photonic crystal fiber designs to support this design/manufacturing tunability whilst also supporting “endlessly single-radial order” modal regimes where the optical fiber is mono-annular over a wide range of optical wavelengths. Such optical fibers being able to support the transmission of a larger diversity of mono-annular modes (OAM or vector modes in nature, or otherwise) in a reliable manner and over a wider range of wavelengths than conventional silica optical fibers.

Abstract: A system and a method for separating rare earth element compounds from a slurry of mixed rare earth element compounds, comprising flowing the slurry of mixed rare earth element compounds through at least a first channel rigged with at least a first magnet along a length thereof and connected to at least a first output channel at the position of the magnet, and retrieving individual rare earth element compounds and/or groups of rare earth element compounds, separated from the slurry as they are selectively attracted by the magnet and directed in the corresponding output channel according to their respective ratio of magnetic susceptibility (??) to specific density (??).