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While spin angular momentum is limited to ±ℏ, orbital angular momentum (OAM) is, in principle, unbounded, enabling tailored optical transition rules in quantum systems. However, the large optical size of vortex beams hinders their coupling to nanoscale platforms such as quantum emitters. To address this challenge, we experimentally demonstrate the subdiffraction focusing of an OAM-carrying beam using a hypergrating, a flat meta-structure based on a multilayered hyperbolic composite. We show that our structure generates and guides high-wave vector modes to a deeply subwavelength spot and experimentally demonstrate the focus of an OAM-carrying beam on a spot size of ∼λ/3. We also show how the proposed platform facilitates the formation of an optical skyrmion with spin textures as small asλ/250, opening new avenues for controlling light–matter interactions. 

We experimentally demonstrate primordial metamaterials - composite media supporting essentially nonlocal wave propagation, grown with molecular beam epitaxy. Our transmission measurements confirm the theoretically predicted spectral signature of coupling to nonlocal modes. 

Abstract Photonic funnels, microscale conical waveguides that have been recently realized in the mid-IR spectral range with the help of an all-semiconductor designer metal material platform, are promising devices for efficient coupling of light between the nanoscales and macroscales. Previous analyses of photonic funnels have focused on structures with highly conductive claddings. Here, we analyze the performance of funnels with and without cladding, as a function of material properties, operating wavelength, and geometry. We demonstrate that bare (cladding-free) funnels enable orders-of-magnitude higher enhancement of local intensity than their clad counterparts, with virtually no loss of confinement, and relate this phenomenon to anomalous reflection of light at the anisotropic material–air interface. Intensity enhancement of the order of 25, with confinement of light to wavelength/20 scale, is demonstrated. Efficient extraction of light from nanoscale areas is predicted. 

We develop a hierarchical approach to building a Physics-guided neural network (PGNN) for scalable solutions of Maxwell equations with high spatial resolution and illustrate the developed formalism on a metamaterial photonic funnel example.