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The quest for more powerful, secure and robust communication devices, transmission and systems is a constant of modern computer science. Light, or the study of photonics and optics, has become a pillar of modern communications with recognised applications such as optical fibre for transfer of vast amounts of data, laser technology.
A lesser-known branch of physics, however, is optomechanics, which is at the intersection of photonics and phononics. Photonics uses the properties of photons in light to transmit information, whereas phononics uses phonons, the quantum of acoustic or vibration energy (sound).
PHENOMEN is laying the foundations for new information technologies and processes based on phonon manipulation and their coupling to photons and radio-frequency electronics. The project is utilising the optomechanical crystals, which can be designed to better control photons and their mechanical motion for specific purposes and operations under different conditions – such as temperature.
Conventional wisdom in optomechanics is that impurities, resulting in so-called ‘optical non-linearity’ or deviations, are bad. The PHENOMEN team have turned that thinking on its head, seeking to create and then tame non-linearity using special channels in crystals, or wave-guides, to deliver next-generation communications and concepts, such as phonon-based processors which are able to synchronise optical data transfer.
The consortium is made up of three leading research institutes, three universities and an industrial partner. Together, they cover the necessary theoretical and practical experience in photonics, phononics, optomechanics, electrical engineering, nanofabrication and modelling.
Data security
One exciting application recently reported by the consortium looks at how optomechanical crystals create what the authors call “chaos-based” data security. Project findings, published in Nature Communications, present the wild dynamics of photons when a laser beam is passed through a silicon optomechanical crystal, or its ‘cavity system’, to be precise.
The photons in the cavity are affected by heat, dispersion and optomechanical factors, which create a chaotic effect that PHENOMEN’s researchers are now able to modulate by smoothly changing the parameters of the laser.
Using optomechanical crystals and integrated chips to deliberately alter the light beam, carrying data through optical fibres, they create a cryptographic effect that can be unscrambled using a code or key at the other end.
These results pave the way for low-cost cryptography using chaos-based optomechanical systems, note the team in a statement.