Congratulations to Abdulsattar Aesa and Chris Walton (University of Hull) for this winning image. The image shows ArF 193 nm laser patterning of chitosan. Abdulsattar explains:
" The 2D cross-grating was realised in chitosan, a biocompatible, using an Argon Fluoride excimer laser. This figure shows small parts of the grating, 5mm × 5mm, measured with a white light interferometer (WLI) WYKO NT 1100. The structure was produced by mask projection and translating the sample in orthogonal directions relative to the stationary 193 nm laser beam. Laser ablation was carried out using a laser fluence of 110 mJcm-2, a pulse repetition frequency of 10 Hz and a motion control stage (Aerotech Fiber Align) velocity of 0.1 mms-1. The column-like structures are 7 microns square and 525 nm high."
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