Fig. 5: Dynamic encoding based on PL intensity modulation via air oxidation.
a A confocal fluorescence image of the diamond-PUF label with an area of 100 µm × 100 µm. b The confocal fluorescence images of the red dashed area of 20 µm × 20 µm in (a) at 3 different times (t0, tx, ty). The color bar is kept the same for different images. c The PL intensity of 10 random diamond microparticles circled in (b) at three different time (t0, tx, ty). d The digitization of decimal encoding of the area shown in (b) based on the PL intensity at each pixel, at a resolution of 25 pixels × 25 pixels. e The similarity index and f Hamming distance (normalized) of the decimal keys generated at the same and different times. g Demonstration of the utilization of the diamond-PUF labels in public and personal anti-counterfeiting systems. The error bars in c, e and f represent standard deviation from at least three independent measurements.
