Fig. 2: Light transport in the Lattice and Spectral-averaged NPR Under Varying Random-Dimer On-site Potential.

a The four simulated trajectories of light inject from the 41st site and propagate in 1000μm long SSH lattices comprising 100 sites with varying degrees of random dimer disorder are displayed. I, II, III, and IV correspond to random-dimer on-site potentials, ϵ = 0, 0.1, 0.185, and 0.3 respectively, with random-dimer assignment probability of p = 0.5. In I, a ballistic light propagation takes place without any disorder present; in II and IV, light becomes localized within the lattice at the designed random-dimer on-site potentials, despite significant propagation distance. III demonstrates the phenomenon of reentrant localization, where both extended and localized states coexist. b The numerically computed spectral-averaged NPR based on eigenstates as a function of random-dimer potential ϵ over a range of lattice sites from 30 to 1000. As the number of lattice sites increases, the spectral-averaged NPR exhibits a declining trend, yet the counterintuitive reentrant peaks consistently emerge. The four light transport simulations coincide with the different regimes in the spectral-averaged NPR plot, as denoted by the color coding and labeling I to IV.