Scientists from the Australian National University (ANU) have designed AlGaAs-based nanoantennas that they say could be used to create lightweight night-vision glasses.
The nanoscale antennas work by interacting strongly with incoming light to transform its frequency, radiation, and polarisation patterns, according to their recent paper published in Nano Letters.
"The nano crystals are so small they could be fitted as an ultra-thin film to normal eye glasses to enable night vision," said Dragomir Neshev from the Nonlinear Physics Centre within the ANU Research School of Physics and Engineering. "This tiny device could have other exciting uses including in anti-counterfeit devices in bank notes, imaging cells for medical applications and holograms."
According to the research paper, the nanodisk AlGaAs antennas were able to emit second harmonic in preferential direction with a backward-to-forward ratio of up to five. They could also generate complex vector polarisation beams, including beams with radial polarisation.
Co-researcher Mohsen Rahmani said the ANU team's achievement was a big milestone in the field of nanophotonics. "These semiconductor nanocrystals can transfer the highest intensity of light and engineer complex light beams that could be used with a laser to project a holographic image in modern displays," said Rahmani, a recipient of the Australian Research Council (ARC) Discovery Early Career Researcher Award based at the ANU Research School of Physics and Engineering.
PhD student Maria del Rocio Camacho-Morales (above) said the team built the device on glass so that light can pass through, which was critical for optical displays. "This is the first time anyone has been able to achieve this feat, because growing a nano semiconductor on a transparent material is very difficult," said Camacho-Morales from the Nonlinear Physics Centre at ANU.
The innovation builds on more than 15 years of research supported by the ARC through CUDOS, a Centre of Excellence, and the Australian National Fabrication Facility.
‘Nonlinear Generation of Vector Beams From AlGaAs Nanoantennas’ by Camacho-Morales et al; Nano Lett., 2016, 16 (11), pp 7191-7197