Harvard Breakthrough May Usher In Era Of Optical Computing

The chips inside our computers today rely on electricity to operate and one of the ways that computers of the future might be significantly faster is by replacing those electrical impulses with light. Light travels much faster than electricity through a copper wire or even a carbon nanotube. Before optical computing can be used in computers and other systems researches have to find a way to make light easier to manipulate at the nanoscale and Harvard scientists think they may have done that.

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences have designed the first on-chip metamaterial that has a refractive index of zero. With a refractive index of zero, the phase of light can travel infinitely fast. The material was developed in the lab of Eric Mazur and consists of a silicon pillar embedded in a polymer matrix, clad in a gold film.

Mazur says that the material allows researchers to bend, twist, and reduce the diameter of the beam of light from the macroscale to the nanoscale. The phase velocity of light changes depending on what material it is passing through and how much the waves and crest of the light change in a material is expressed as the refraction index. Water has a refraction index of 1.3.

In a material with a zero refraction index light no longer travels as a wave and there is no phase advance. That lack of phase advance lets light travel as infinitely long wavelengths. This allows the light to be manipulated without losing energy and the scientists think that using the zero-index material on a chip could have significant applications in the world of quantum computing.

SOURCE: Harvard