Scientists discover how to send data with light


Researchers from the Connectivity Laboratory, a partnership between Facebook and six other companies, may have found a way to transmit large volumes of data through light without using optical fibers. To this end, the team used plasmonics, a technology that uses ripples in the electrons of a metal generated by the incidence of a beam of light, and measured the electric wave to decode what the light generated.

So far, there are no alternatives to transmit data in this way. This is because, without the presence of optical fiber, it is difficult to identify what is given and what is just lighting. Therefore, if applied, this discovery will represent a significant advance in the science and speed of the Wi-Fi connection.

Light antennas

In technical terms, the challenge is in the construction of photodetectors (or “light antennas”) that have high efficiency and directionality, so that sparse lights are not detected. Other scientists have already concluded that, in order to solve this problem, the equipment should be multidirectional. However, this raises a new question: as the optical sensor is increased, it slows down, canceling the gains in communication speed.

Using plasmonic technology, the team built several antennas with 60-nanometer-wide silver cubes that functioned as sensors. The next step was to position the antennas at an average distance of 200 nanometers and insert a thin layer of silver in the intervals, spaced by a polymer coating filled with 4 layers of fluorescent dye.

In this structure, the cubes interact with the silver base, expanding the phototonic capacities of the fluorescent dye by 910 times and the emission rate by 133 times. As a result, the system captured light from a 120 degree field of view and converted it into a directional source with a record efficiency of 30%. In other words, the team was able to capture light from a wide field of view and funnel it into a narrow cone – all without slowing down.


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