Ideal Magnetic Quadrupole Radiators

High-purity magnetic quadrupole (MQ) radiation enables unique directional and chiral light-matter interactions inaccessible to low-order multipoles, yet its practical implementation is fundamentally limited by two long-standing bottlenecks: ultralow radiative transition rates and severe modal hybridization with parasitic low-order modes. Here, we theoretically propose and numerically demonstrate a universal synergistic strategy combining parity-selective mode filtering and anapole engineering to realize ideal MQ radiation. Our design achieves >99.8% MQ modal purity with a perfectly symmetric four-leaf clover far-field profile under both far-field plane-wave and near-field dipole excitation. Critically, this mechanism enables direct, contamination-free conversion of fundamental electric dipole (ED) emission into pure MQ radiation under the near-field dipole regime—the dominant platform for on-chip quantum light sources. This work establishes a robust paradigm for deterministic high-order magnetic multipole manipulation, with immediate applications in quantum light sources, magneto-optics, and topological photonics.