2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/91428We have experimentally observed superluminal and infinite group velocities in bulk hexagonal two-dimensional photonic bandgap crystals with bandgaps in the microwave region. The group velocities depend on the polarization of the incident radiation and the air-filling fraction of the crystal.8 pages, 7 figuresQuantum Physicstext