Localization and reentrant delocalization transitions in one-dimensional photonic quasicrystals

Waves propagating in certain one-dimensional quasiperiodic lattices are known to undergo a sharp localization transition at a finite disorder strength. We theoretically predict and experimentally demonstrate that the localization of light in one-dimensional photonic quasicrystals is followed by a reentrant delocalization transition when the quasiperiodic modulation strength is increased well beyond the localized regime. We further demonstrate that this phenomenon can be qualitatively captured by a dimerized tight-binding model with long-range couplings. Our findings shed light on the physics of localization in complex systems and the impact of quasiperiodicity on light transport in photonic devices.