Experimentally, strong localization of electromagnetic waves in three dimensions has never been achieved, despite extensive studies. Moving away from the paradigm of disordered systems, we perform microwave transport experiments in planar aperiodic Vogel spiral arrays of cylinders with high dielectric permittivity. By characterizing the electromagnetic modal structure in real space, we observe combinations of long-lived modes with Gaussian, exponential, and power law spatial decay. This distinctive modal structure, not present in conventional photonic materials with periodic or disordered structures, is the cause of significant electromagnetic wave localization that persists even in a three-dimensional environment.
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