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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. 

Abstract Efficient optical coupling between nano‐ and macroscale areas is strongly suppressed by the diffraction limit. This work presents a possible solution to this fundamental problem via the experimental fabrication, characterization, and comprehensive theoretical analysis of structures referred to as “photonic funnels.” The funnels represent a novel composite material platform that combines hyperbolic dielectric response with geometry‐assisted optical confinement. Experimentally, funneling of mid‐infrared light through openings with diameters as small as 1/25th of the free space wavelength (λ₀) is demonstrated. By analyzing the optical response of the funnels, as fabricated, both confinement of mid‐infrared radiation to the λ₀/25 areas and efficient outcoupling of light from deep subwavelength areas are confirmed. 

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 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. 

Photonic funnels have been demonstrated as a flexible platform to confine light to deep subwavelength spatial areas. Here we consider the utility of this platform to provide temporal, as well as spatial, light shaping. 

We analyze the interaction between a nanoscale emitter and a photonic funnel with a metamaterial core and demonstrate that funnel structures can significantly improve out-coupling efficiency of light as compared with their planar plasmonic counterparts. 

Light with an orbital angular momentum can strongly modify optical transition selection rules when beam size is reduced to subwavelength scale. We demonstrated a method for focusing orbital angular momentum beams below the diffraction limit 

We analyze, numerically and experimentally, deep subwavelength focusing of light in new material platform, photonic funnels, implemented at infrared frequencies with semiconductor based hyperbolic metamaterials, as function of material concentration, geometric profile, and cladding characteristics