Creating an optical antenna

We are used to the idea of radio antennas, we see them everywhere. On the contrary the concept of an optical antenna sounds unusual. As a matter of fact optics is about waves, similar to radio. It just looks into waves at a higher frequency (and it prefers to talk about them in terms of wavelength, rather than frequency but a we know one is related to the other through the speed of light!).
Antennas are all about emission and reception of waves. In the case of optical ways, ray beams, since the invention of the laser most of the studies and of applications have been on stimulated light emission (LASER: Light Emission by Stimulated Electromagnetic Radiation) and the spontaneous emission has been basically forgotten.
Now a team of researchers at Berkely have found a way to create an antenna that can enhance the spontaneous emission of optical radiation from atoms, molecules and semiconductor quantum dots. This is nothing new, LED, Light Emitting Diodes, are exactly that but their "efficiency" is low in comparison to a Laser. 
By inventing this antenna the researchers are able to create much more efficient LED that can replace a Laser in an electronic circuit to send information inside a chip. The advantage is twofold: the spontaneous emission is much faster than Laser and the antenna is much much smaller so that it can be embedded hundreds of millions of times in a single chip.
Spontaneous emission occurs … spontaneously, but to make use of it you need to harvest many of these spontaneous emission. This is what the researchers have done by covering a square shaped nanorod made of InGaAsP with titanium dioxide isolating the rod from a gold wire placed perpendicularly to the rod that works as an antenna. The emission is provided by the InGaAsP rod.
Optical communication in a chip (or as a substitute of a printed board to connect chips) can dramatically reduce power consumption (hence heat generation) thus fostering increasing density and miniaturisation….

About Roberto Saracco

Roberto Saracco fell in love with technology and its implications long time ago. His background is in math and computer science. Until April 2017 he led the EIT Digital Italian Node and then was head of the Industrial Doctoral School of EIT Digital up to September 2018. Previously, up to December 2011 he was the Director of the Telecom Italia Future Centre in Venice, looking at the interplay of technology evolution, economics and society. At the turn of the century he led a World Bank-Infodev project to stimulate entrepreneurship in Latin America. He is a senior member of IEEE where he leads the New Initiative Committee and co-chairs the Digital Reality Initiative. He is a member of the IEEE in 2050 Ad Hoc Committee. He teaches a Master course on Technology Forecasting and Market impact at the University of Trento. He has published over 100 papers in journals and magazines and 14 books.