Photonic crystal and photonics glass
Description: Nano silica particles can be packed in a crystalline or disordered structure. The reflected color depends on the particle size and the inter distance between particles. On the left hand side, we display opal materials that consist of 220 nm silica particles, which are packed in a crystalline structure.
New coating method (PRL Editors' suggestion) 
Description: A new particle coating method is introduced, inspired by a dried mark of whisky. A comparison of dried marks of an actual whisky drop (top left), a whisky drop with fluorescent particles (top right), and a model liquid with fluorescent particles (bottom).

Related publication: Kim et al. “Controlled uniform coating induced by multiple Marangoni flows and surface-adsorbable macromolecules,” accepted, PHYS REV LETT.
Cave of crystals
Description: Watch any liquid – from tap water to the richest coffee – evaporate off a surface and you will see it leave a unique, ghostly mark. Here, we deposited a dilute solution of bovine serum albumin – a protein from cow’s blood. As the solution droplet evaporated, the protein is crystallized and left a delicate pattern similar to that seen in snowflakes. It is so-called “dendritic crystallization”. As time passed, more and more moisture evaporated, crystallizing – layer upon layer – a crystal cave that represents, to us, the need to dig deeper into layer upon layer of scientific discovery.
2014 Art of Science, Princeton University