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We demonstrate experimentally Bloch oscillations, which occur above a certain threshold value of the effective potential gradient in lattices with specially modulated coupling between the neighboring sites. We formulate the general conditions for this phenomenon, arising due to the competition between the tilting and broadening of the transmission band, and explain why no threshold was present in any previous observations. Our experiments are performed in inhomogeneous photonic lattices, which represent the process of quantum two-mode squeezing in Fock space, underpinning a fundamental quantum-classical correspondence.

We experimentally demonstrate that disorder can induce a topologically non-trivial phase. We implement this “Topological Anderson Insulator” in arrays of evanescently coupled waveguides and demonstrate its unique features.

We investigate the interplay of Bloch oscillations and Anderson localization in optics. Gradual washing out of Bloch oscillations and the formation of nearly stationary averaged intensity distributions, which are symmetric for narrow and strongly asymmetric for broad input excitations, are observed experimentally in laser-written waveguide arrays. At large disorder levels Bloch oscillations are completely destroyed and both narrow and wide excitations lead to symmetric stationary averaged intensity distributions with exponentially decaying tails., Peer Reviewed, Postprint (published version)

We report Anderson localization in two-dimensional optical waveguide arrays with disorder in waveguide separation introduced along one axis of the array, in an uncorrelated fashion for each waveguide row. We show that the anisotropic nature of such disorder induces a strong localization along both array axes. The degree of localization in the cross-axis remains weaker than that in the direction in which disorder is introduced. This effect is illustrated both theoretically and experimentally., Peer Reviewed, Postprint (published version)