A three-dimensional optical photonic crystal

We report on the successful fabrication of a working three-dimensional (3D) crystal operating at optical wavelength /spl lambda/. The minimum feature size of the 3D structure is 180 nm. The 3D crystal is free from defects over the entire 6-inch silicon wafer and has an absolute photonic bandgap (PBG) centered at /spl lambda//spl sim/1.6 /spl mu/m. Our data provides the first conclusive evidence for the existence of a complete 3D PBG in optical /spl lambda/. This development will pave the way to tinier, cheaper, more effective waveguides, optical switches and lasers.