  Anderson localization is a striking phenomenon wherein transport of light is
arrested due to the formation of disorder-induced resonances. Hitherto,
Anderson localization has been demonstrated separately in two limits of
disorder, namely, amorphous disorder and nearly-periodic disorder. However,
transport properties in the two limits are yet unstudied, particularly in a
statistically consistent manner. Here, we experimentally measure light
transport across two-dimensional open mesoscopic structures, wherein the
disorder systematically ranges from nearly-periodic to amorphous. We measure
the generalized conductance, which quantifies the transport probability in the
sample. Although localization was identified in both the limits, statistical
measurements revealed a discrepant behavior in the generalized conductance
fluctuations in the two disorder regimes. Under amorphous disorder, the
generalized conductance remains below unity for any configuration of the
disorder, attesting to the arrested nature of transport. Contrarily, at
near-periodic disorder, the distribution of generalized conductance is
heavy-tailed towards large conductance values, indicating that the overall
transport is delocalized. Theoretical results from a model based on the
tight-binding approximation, augmented to include open boundaries, are in
excellent agreement with experiments, and also endorse the results over much
larger ensembles. These results quantify the differences in the two disorder
regimes, and advance the studies of disordered systems into actual consequences
of Anderson localization in light transport.
