Spatial Periodic Perturbation of Turing Pattern Development Using a Striped Mask

We study the influence of the intensity of light and the wavelength of an imposed parallel striped mask on the development of striped Turing patterns. Depending on the ratio R ) λF/λP of the wavelength of the mask to the wavelength of the natural pattern and on the amplitude of forcing, stripes develop parallel or perpendicular to the orientation of the mask. For R near 1.5 or 3, zigzag patterns develop. When weak forcing is applied, stripe splitting is observed for R near 2. For strong forcing, stripe splitting occurs over a wider range of R, and two sequences of splitting are observed when R ) 4. At large R, fingers of spreading patterns develop, which propagate and reconnect to form stripes perpendicular to the mask orientation.