Fibers Thinner Than Wavelengths of Light

ARLINGTON, Va., Dec. 23 -- Researchers have developed a process to create wires only 50 nanometers (billionths of a meter) thick. Made from silica, the same mineral found in quartz, the wires carry light in an unusual way: Because the wires are thinner than the wavelengths of light they transport, the material serves as a guide around which light waves flow. In addition, because the researchers can fabricate the wires with a uniform diameter and smooth surfaces down to the atomic level, the light waves remain coherent as they travel.

HOW THIN IS IT? A light-conducting silica nanowire wraps a beam of light around a strand of human hair. The nanowires are flexible and can be as slender as 50 nanometers in width, about a thousandth the width of a hair. (Photo: Limin Tong/Harvard University)

The smaller fibers will allow devices to transmit more information while using less space. The new material may have applications in ever-shrinking medical products and tiny photonics equipment such as nanoscale laser systems, tools for communications and sensors. Size is of critical importance to sensing -- with more, smaller-diameter fibers packed into the same area, sensors could detect many toxins, for example, at once and with greater precision and accuracy.

Researchers at Harvard University led by Eric Mazur and Limin Tong (also of Zhejiang University in China), along with colleagues from Tohoku University in Japan, reported their findings in a recent issue of the journal Nature.

The National Science Foundation (NSF), a pioneer among federal agencies in fostering the development of nanoscale science, engineering and technology, supports Mazur's work. In fiscal year 2004, NSF requested an expansion over earlier investments in critical fields including nanobiotechnology, manufacturing at the nanoscale, instrumentation and education. These efforts will enable development of revolutionary technologies that contribute to improvements in health, advance agriculture, conserve materials and energy and sustain the environment. The research will help establish the infrastructure and workforce needed to exploit the opportunities presented by nanoscale science and engineering.

"Dr. Mazur's group at Harvard has made significant contributions to the fields of optics and short-pulse laser micromachining," said Julie Chen, director of NSF's nanomanufacturing program. "This new method of manufacturing subwavelength-diameter silica wires, in concert with the research group's ongoing efforts in micromachining, may lead to a further reduction of the size of optical and photonic devices."

For more information, visit: mazur-www.harvard.edu