Light and its cybernetics applications have fascinated researchers for a long time. Since light travels and it does so at high speeds (currently nothing that we know of surpasses the speed of light), manipulating light particles to carry information and messages represents a scientific desideratum. While light already carries signals in optic fiber cables, the difficulty of photon manipulation made researchers unable to progress towards using light in computing. Researchers dreamed of a wonder metamaterial.
A previous (and different) attempt of photon manipulation
Harvard University has a history in this field of research. In 1998 it was part of a combined team that succeeded in slowing a beam of light at about 17 meters per second. Continuing his research, one of the physicists from the initial combined team (the Danish Lene Vestergaard Hau) developed methods that allowed her to stop and restart a beam of light. This was accomplished in 2013. Photons were not actually manipulated as much as used to carry signals in a quantum network, bypassing the control-ability issue. In this experiment, the light beam is finally extinguished once it reaches its destination point and reactivated in its original pulse form – in a separate atoms cloud. Slowing light beams thus reached its maximum point via this method.
Controlling the optical environment for information delivery is extremely important for the future of quantum computing. Modifying phase velocity (the rate of light wave crests movement when propagating through a material) is another experiment that recently marked a breakthrough – by creating a material that allows an infinite phase speed, “infinitely larger than the speed of light”. The speed of light remains the same, yet the light wave crests move infinitely fast.
The metamaterial breakthrough in light manipulation
A metamaterial is a smart, man-engineered material that displays artificial properties, unknown so far in nature. The history of such attempts dates back to the 19th century, when electromagnetic waves manipulation required exploring such materials. Over the years, metamaterials have been developed and employed in constructing antennas, super lens, cloaking devices or seismic protection structures.
The Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) team of physicists conducted by Eric Mazur recently created the first on-chip integrated metamaterial that makes manipulating photons similar to manipulating electrons, therefore opening possibilities for light-powered telecommunications.
Their material reduces the refraction index to zero and allows for the light to be manipulated “from one chip to another” and “to squeeze, bend, twist and reduce diameter of a beam from the macroscale to the nanoscale”, without losing energy.
The Harvard team describes the material as consisting of a polymer matrix with embedded silicon pillar arrays, all clad by gold film. Such structure couples efficiently with previously existing optical elements.
Explaining the metamaterial breakthrough
In attempts of translating science terms into nonprofessional’s language and more visual concepts, various articles that expand on this piece of news explain that the discovery opens up a possibility for superfast phones and computers, all the while requiring a lesser energy consumption. Considering that tech science is striving to meet the quantic computing with efficient hardware and software solutions that would also respond to the overheating issue with a technological upgrade/makeover – the metamaterial discovery announced by Harvard falls into line with other research projects on how the future of computing and communications will look like.
However tech passionate we might be, it might prove difficult to understand how in this environment offered by the newly discovered material, the light wave oscillates in time instead moving through space. The wave crests have been altered by the zero-refraction index, their shape and properties changed in a way that determines them only by time and not by space-related movement.
Without diving into more sophisticated quantum optics theories when trying to grasp the inherent technological applications, it is however important to realize the meaning and scale of the Harvard breakthrough. Another Endgadget article summarizes the entire paradigm and may help in better understanding what an extremely important step this is in photon-based computing. Disposing of a refractive material that has a refraction index of zero determines light waves to stretch infinitely while passing through the said material, practically turning into a flat line. Inside such a flat line the photon oscillations are only time-relative, not space-relative. Moreover, as Philip Mazur, one of the research paper’s coauthors, states “the lack of phase advance would allow quantum emitters in a zero-index cavity or waveguide to emit photons which are always in phase with one another” – therefore manipulating light without losing energy.
Add to this Yang Li’s statement (first author): “This zero-index metamaterial offers a solution for the confinement of electromagnetic energy in different waveguide configurations because its high internal phase velocity produces full transmission, regardless of how the material is configured”, and maybe in an effort of imagination we can visualize light as a wire for carrying messages at a very high speed and with low energy consumption. True as it may be that such characteristics depend of the metamaterial and that there are still other steps to be made before the discovery reflects into technology, it is nevertheless impressive.
The zero-index metamaterial created at SEAS opens up new horizons in quantum computing, and raises expectations and hopes for the technology of the future coming sooner than expected when using the traditional electron manipulating methods.
