Spatially Shaping Waves to Penetrate Deep inside a Forbidden Gap

It is well known that waves incident upon a crystal are transported only over limited distance - the Bragg length before being reflected by interference. Here, we demonstrate how to send much deeper into crystals, studying light in exemplary two-dimensional silicon photonic crystals. By spatially shaping optical wavefronts, observe intensity of laterally scattered light, probes internal energy density, enhanced at tunable away from front surface. The up $100 \times$ compared random wavefronts and extends as far $8 length. Our novel steering inside forbidden gap exploits transport channels induced unavoidable deviations perfect periodicity, here fabrication deviations.