Fig. 4: Generation and characterization of stochastic processes across multiple length scales. | Nature Communications

Fig. 4: Generation and characterization of stochastic processes across multiple length scales.

From: Bright and stable anti-counterfeiting devices with independent stochastic processes covering multiple length scales

Fig. 4

(a) Real-time observation of the microstructures formed by the decomposition of positive photoresist AZ 4562. The exposure process was performed by hard contact under 365 nm UV irradiation with an intensity of 3 mW/cm2. b) Fractal structures with different complexity were generated by fine-tuning the lithography parameters. The ratios of SU 8 2002 to AZ 4562 and UV exposure time from left to right are 6:1, 120 s; 5:1, 120 s; 4:1, 120 s; 5:1, 80 s respectively. c) Stochastically distributed photoresist spot arrays can be binarized and encoded. d) The entropy along the x-axis and y-axis of the binarized bits, showing the randomness of the stochastic process. Source data are provided as a Source Data file.

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