  We study both, experimentally and theoretically, propagation of light in the
fs-laser written rotating square waveguide arrays and present the first
experimental evidence of light localization induced by the rotation of periodic
structure in the direction of light propagation. Such linear light localization
occurs either in the corners of truncated square array, where it results from
the interplay between the centrifugal effect and total internal reflection at
the borders of truncated array, or in the center of array, where rotation
creates effective attractive optical potential. The degree of localization of
linear bulk and corner modes emerging due to the rotation increases with the
increase of rotation frequency. Consequently, corner and bulk solitons in
rotating wave-guide arrays become thresholdless for sufficiently large rotation
frequencies, in contrast to solitons in non-rotating arrays that exist only
above power threshold. Focusing nonlinearity enhances localization degree of
corner modes, but surprising initially it leads to broadening of bulk nonlinear
states, followed by their re-localization at high input powers. Our results
open new prospects for control of evolution of nonlinear multidimensional
excitations by dynamically varying potentials.
