Scale-free optics and diffractionless waves in nano-disordered ferroelectrics

Waves have a limited capability of discerning spatial details due to their finite wavelength. Here we experimentally demonstrate optical waves that propagate in an intensity-independent scale-free regime, as if their wavelength is negligibly small. In our experiments, highly focused and diffracting laser beams are made to propagate in the bulk lithium enriched potassium-tantalate-niobate (KTN:Li) doped with Cu impurities, a newly engineered optical quality non linear photorefractive crystal whose nonlinear scales can be artificially enhanced and tuned because of its room temperature non-ergodic phase.