Negative refraction in tunable periodic photonic structures

Abstract

We predict theoretically and observe experimentally tunable refraction of beams in optically-induced lattices. By selective excitation of different Bloch modes in a tilted lattice, we observe positive and negative refraction for beams associated with the first and the second spectral band, respectively. We demonstrate tunability of the output beam position by dynamically adjusting the lattice depth. At higher laser intensities, the beam broadening due to diffraction can be suppressed through nonlinear self-focusing while preserving the general steering properties. Show more