# Interface localization for the lattice site excitation in the first row of the square lattice

**Figure 1.** Interface localization for the lattice site excitation in the first row of the square lattice. (a) System geometry with the cross marks the location of the input Gaussian beam. Typical examples of averaged localized modes for the 20% disorder level are shown for: (b) *V*_{0s} = 3, *V*_{0h} = 3.5, (c) *V*_{0s} = *V*_{0h} = 3 and (d) *V*_{0s} = 3.5, *V*_{0h} = 3. (e) Effective beam width at the lattice output is shown as a function of the disorder level, for varying lattice intensities. Points are ensemble averages and lines are the least-squares fits through the points. Error bars depict the spread in values coming from statistics. Physical parameters are: the crystal length *L* = 20 mm, square lattice period 15 μm, hexagonal lattice period 13 μm, input beam intensity |*E*_{0}|^{2} = 0.5, input beam FWHM = 10 μm.

**Abstract**

The Anderson localization of light at the interface separating square and hexagonal photonic lattices is demonstrated numerically. The influence of varying lattice intensities and disorder level on the transverse localization of light is discussed. Both suppression and enhancement of light localization in the presence of the interface, depending on the difference in the lattice intensity in both regions, and the position of the excited lattice site are demonstrated. Such localization is compared to the cases with no interfaces. Also, it is analysed how the presence of a phase-slip defect modifies the phenomenon of Anderson localization of light at the interface.