Silica Nanowires
Liming Tong, Rafael R. Gattas, and Eric Mazur

To use silica nanometer-diameter wires as building blocks for integrated microphotonics devices, the wires must be mounted on a substrate without losing their optical wave guiding properties. We address this problem by using silica aerogel as a substrate. Because the refractive index of an aerogel is very close to that of air, the optical guiding properties of aerogel-supported wires are virtually identical to those of air-clad ones. (a) is a scanning electron image of a 450-nm diameter silica wire supported on a substrate of silica aerogel. (b) is an optical microscopy image of a silica wire guiding light on the surface of silica aerogel.