Disentangling Optical Transport Regimes in Hyperuniform Photonic Materials Via Transverse Beam Spreading

Disordered stealthy hyperuniform (SHU) dielectric slabs exhibit distinct optical transport regimes, including diffusive transport, localization, and photonic bandgaps. Here, we present a robust, absorption‐tolerant method to identify these regimes from a single disordered slab by analyzing the transverse spreading of a focused beam at the output plane. For frequencies far from the bandgap, rapid spreading of the transmitted intensity toward the slab edges indicates diffusive behavior. Conversely, strong transverse confinement of the transmitted intensity near the gap signals the presence of Anderson localization, Lifshitz‐tail modes, or a photonic bandgap. Our results establish beam‐spreading analysis as a practical diagnostic tool for complex photonic materials that is readily applicable to both numerical and experimental platforms.