Pattern Guiding via “Structured Noise”

Far-from equilibrium systems, such as reaction diffusion systems, exhibits the unique feature of pattern formation [1]. Nonlinear variations of these systems further enrich observed patterns and underlying dynamics [2,3]. Here, we show that, in recently developed Nonlinear Laser Lithography (NLL) [4] and Swift-Hohenberg systems, it is possible to control the emerging patterns employing engineered defects in the form of "structured noise". In NLL, "structured noise" enables us to tile the material surface with all possible periodic structures of isotropic unit cells, namely Bravais lattices. The nanopatterning is demonstrated both in simulations and experiments. Using similar approach with the Swift-Hohenberg system, we numerically show that pattern selection and direction can be achieved with initial defects. As a characteristic feature of such systems that are responsive to noise, we demonstrate stochastic resonance behavior in both systems. The control capability arises due to thresholding behavior of pattern transitions based on nonlinear feedback mechanisms.

[1] Turing, A. M., Phil. Trans. R. Soc. B, 237,32-72 (1952).
[2] Ilday, S. et al., Nat. Comm. 8,(2017).
[3] Tokel, O. et al., Nat. Photonics 11,639-645 (2017).
[4] Oktem, B. et al., Nat. Photonics 7,897-901 (2013).