A Nanoantenna for Long-Distance, Ultra-Secure Quantum Communication

A conceptual diagram of the efficient illumination of photons to the lateral quantum dots of a semiconductor using surface plasmon antennas and the excitation of electrons within the quantum dots. Credit: Copyright @ 2021 Oiwalab.all rights reserved

Researchers at Osaka University have improved transfer efficiency between quantum information carriers in a way that is based on established nanoscience and compatible with future advanced communication technologies.

The storage and transfer of information in simple 1- and 0 ways, as in today’s classic computer technology, is inadequate for the quantum technology under development. Currently, Japanese researchers have created nanoantennas that will help bring quantum information networks closer to practical use.

In a recently published study Applied Physics ExpressResearchers and collaborative partners at Osaka University have significantly enhanced photon-to-electron conversion through metal nanostructures. This is an important step in the development of advanced technologies for sharing and processing data.

Traditional computer information is based on simple on / off readings. It is easy to amplify and retransmit this information over long distances using a technology called repeaters. Quantum information is based on relatively complex and safe readouts such as photon polarization and electron spin. Semiconductor nanoboxes, known as quantum dots, are materials proposed by researchers to store and transfer quantum information. However, quantum repeater technology has some limitations. For example, the current method of converting photon-based information to electronic-based information is very inefficient. Overcoming this information transformation and transfer challenge is aimed at the efforts of researchers at Osaka University.

“The efficiency of converting a single photon into a single electron with gallium arsenide quantum dots, a common material in quantum communication research, is currently too low,” explains lead author Rio Fukai. “Therefore, we designed a nanoantenna consisting of gold microconcentric rings to focus the light on a single quantum dot. As a result, the voltage was read from the device.”

Researchers have increased photon absorption by up to 9 times compared to without a nanoantenna. After irradiating a single quantum dot, most of the photogenerated electrons were not trapped there, but instead accumulated in impurities or elsewhere in the device. Nonetheless, these excess electrons provided the minimum voltage readout that was easily distinguished from that produced by the quantum dot electrons, and thus did not interfere with the intended readout of the device.

“Theoretical simulations have shown that photon absorption can be improved up to 25 times,” said senior author Akira Oiwa. “Improved light source placement and more accurate manufacturing of nanoantennas is the direction of ongoing research in our group.”

These results have important uses. Researchers now have the means to use established nanophotonics to advance the outlook for future quantum communications and information networks. By using abstract physical properties such as entanglement and superposition, quantum technology has the potential to provide unprecedented information security and data processing in the coming decades.

Reference: “Detection of light-generating single electrons in lateral plasmon dots using surface plasmon antenna”, Rio Fukai, Yuji Sakai, Takafumi Fujita, Haruki Kiyama, Arne Ludwick, Andreas D. Wick, Akira Oiwa, 2021 November 9, 2014 Applied Physics Express..
DOI: 10.35848 / 1882-0786 / ac336d

A Nanoantenna for Long-Distance, Ultra-Secure Quantum Communication Source link A Nanoantenna for Long-Distance, Ultra-Secure Quantum Communication

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