Physical Society Colloquium

Wrapping light around a hair

Eric Mazur

Harvard Universirty

Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was no. We developed a technique for drawing long, freestanding silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it possible to control the propagation of light around micrometer-sized corners. The nanowires have applications in microphotonic devices for optical processing and environmental sensing.