Photonic bandgaps are three-dimensional structures that can reflect electromagnetic radiation in a band of frequencies propagating in any direction. Scientists from the Max Planck Institute for Biophysical Chemistry have fabricated such structures using laser rapid prototyping via laser-induced direct-write deposition from the gas phase. To do this, they employed a continuous-wave argon-ion laser operating at 488 nm and approximately 2 mW, focusing to a spot size with a diameter of 5 µm. The team calls the aluminum oxide microstructures unique because they can customize the optical properties to fabricate perfect mirrors, lasers without threshold and special optical waveguide devices. Advantages of the technique include the ability to grow photonic crystals around devices already present on a wafer and to locally dope material during growth. The team published its findings in a recent issue of the journal Science.