Experimental signature of a broad 3D photonic band gap in silicon nanostructures

Three-dimensional photonic crystals radically control propagation and emission of light. Photonic crystals are ordered composite materials with a spatially varying dielectric constant that has a periodicity of the order of the wavelength of light. In specific three-dimensional crystals, a common frequency range for all polarizations is formed for which light is not allowed to propagate in any direction, called the photonic band gap. It is an outstanding challenge to create these crystals and experimentally demonstrate the photonic band gap.