Holographic patterning of fluorescent microstructures comprising silver nanoclusters

Metal nanoclusters, which exhibit extraordinary physical and chemical properties that are different from their bulk counterparts, are highly promising nanomaterials for photonics. Recently, the use of twophoton excitation to fabricate silver nanoclusters in polymers was reported but still lacks speed and flexibility which are imperative for applications such as labeling and spectroscopy. Here, we demonstrate the fabrication of fluorescent nanocluster microstructures using spatially phase-shaped laser beams. Using an incident power of 60 mW and exposure time of 8 s, we found that the smallest line-width of the fluorescent microstructures is 478 nm, which is comparable to the line-width achieved with a two-photon laser scanning approach. As a proof-of-principle demonstration, the technique is used to fabricate fluorescent micro-labels that could be used in anticounterfeiting applications.