If I want to color something gold, I reach for a chemical pigmented spraypaint — or possibly for gold leaf. But a beetle from Costa Rica gives the appearance of being gold using a diffraction grating built into the layers of it’s shell.
Oddly enough, being bright allows the beetle to blend in with it’s surroundings: amid the rainforest, it reflects light a lot like a drop of water.
Read more in my story at Optics & Photonics News: Metallic Beetles May Inform Nanoengineering.
The actual paper is available in open-access journal: Optical Materials Express at Visible light reflection spectra from cuticle layered materials