Non-Hermitian control of localization in mosaic photonic lattices

Exploring the deep insights into localization, disorder, and wave transport in non-Hermitian systems is an emergent area of research of relevance in different areas of physics. Engineered photonic lattices, with spatial regions of optical gain and loss, provide a prime and simple physical platform for tailoring non-Hermitian Hamiltonians and for unveiling the intriguing interplay between disorder and non-Hermiticity. Here it is shown that in mosaic photonic lattices with on-site uncorrelated disorder or quasi-periodic order, the addition of uniform loss at alternating sites of the lattice results in the suppression or enhancement of wave spreading, thus providing a simple method for non-Hermitian control of wave transport in disordered systems. The results are illustrated by considering discrete-time quantum walks in synthetic photonic lattices.