Plasmonic nanoantennas could improve photonic chips

Researchers from the Polytechnic University of Valencia (UPV) have designed silicon nanoantennas with direct applications in communication and data processing for the next generation of reconfigurable photonic chips. Described in the journal ACS Photonics, this type of configuration opens the door to the development of miniature nanobiosensors and to the design of future systems and networks based on quantum optics.

The research combines the benefits of dielectric wireless applications — for the design of reconfigurable networks, creating beams or biosensors — and plasmonics, based on the use of metallic devices and interconnections for the ultrafast conversion of data or light engineering at nanometric levels. This opens the path to a new generation of integrated hybrid networks.

“We experimentally proved the first wireless dielectric–plasmonic connection thanks to a new type of dielectric nanoantenna that overcomes the limitations that plasmonics had until now, opening the door to new hybrid configurations,” said Javier Martí, Head of the Valencia Nanophotonics Technology Center (NTC).

“The results we have obtained have a direct implication in the design of reconfigurable communication networks inside the chip, in the development of ultrafast optic devices and in the practical implementation of ultracompact biosensors. Thanks to plasmonic structures, this also opens the door to the creation of interfaces with future quantum systems.”

As Sergio Lechago, researcher at the NTC and co-author of the study, explained, plasmonic devices have enabled the development of important applications in fields such as spectroscopy, near-field and sensing optic microscopy thanks to their unique capability of manipulating light on a nano level. Within the communications integrated in the chip, plasmonics enable the development of ultracompact devices (modulators, detectors or sources) that can function at very high operation speeds with low energy consumption.

“The natural way of interconnecting these devices in the optic chip is by using metallic nanoguides,” said the NTC’s Carlos García Meca, a co-author on the study. “However, guiding light through these devices leads to very high propagation losses and entails certain restrictions regarding reconfigurability.

“The use of plasmonic nanoantennas has been proposed to replace and improve the performance of guided metallic interconnections, but these antennas have low directivity and high losses which hinder their use in many practical applications. In this work, we overcame all these limitations by introducing a new dielectric nanoantenna design that acts as an efficient interface for plasmonic systems. This makes it possible to combine the benefits of plasmonics with those of silicon photonics, which can lead to more efficient, fast and reconfigurable chips.”

The breakthrough could also be applied to fields such as biochemical or agrifood industries, thanks to the role that these hybrid systems can carry out as sensors with multiple purposes, allowing the interaction of light with nanoscopic organic and inorganic structures.

Image courtesy of the researchers.

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