Creator of photonic crystals wins Newton medal

Both researchers built on an idea put forward 100 years earlier in 1887, by British physicist Lord Raleigh. He suggested that a material with a repeating, regular structure - such as a crystal - could block light of particular wavelengths.
This happens, Raleigh calculated, because if the light has a wavelength that is similar to the size of the repeated units in the structure, then the waves reflected off its internal surfaces will interfere and cancel each other out. That produces a "stop band" (later called a "photonic bandgap") - a range of light wavelengths that will be repelled by the crystal.