Skoltech researchers, in collaboration with Bergische Universität Wuppertal, Germany, have achieved a major milestone in the quest for optical computers. They have created a universal NOR logic gate, a critical component for performing calculations without using electrical currents. This groundbreaking work, published in *Nature Communications*, signifies a significant step towards the realisation of optical computing, a technology with the potential to be hundreds of times faster than conventional electronic computers.
The new NOR gate, built using polariton condensates, operates at room temperature and features multiple inputs, allowing for complex computations. Unlike its electronic counterparts, it operates entirely with light, eliminating the need for electrical currents. Moreover, these logic gates can be interconnected and cascaded to form more complex circuits.
This research addresses a critical bottleneck in the development of optical computing: the lack of efficient optical logic elements. Existing electronic computers rely on transistors, which, despite advancements, are limited to a few gigahertz in operating frequency due to inherent physical constraints. However, the researchers highlight the potential of polaritons, which can operate at terahertz frequencies, theoretically offering speed increases of up to 300 times compared to electronic transistors.
Previous research by the same team demonstrated the capability of a single photon to control an optical polariton transistor, a feat not achievable with other optical systems. This development, coupled with the recent breakthrough of the universal NOR gate, underscores the potential of polariton-based technology for revolutionising computing.
The team harnessed the unique properties of "liquid light", the term given to polariton condensates. These condensates, capable of amplifying weak optical signals by thousands of times, were previously limited to ground-state condensation, similar to the formation of water droplets on a cold surface. However, the researchers successfully achieved condensation in a non-ground state at higher energy levels. This breakthrough enabled them to create a fully optical NOR gate, allowing for the control of optical signals with light itself.
This innovation addresses a long-standing challenge in optical computing â the difficulty of manipulating light signals to achieve logical operations. The team's research proves that by utilising the unique properties of polariton condensates, this hurdle can be overcome, paving the way for the development of optical computers.
The potential impact of this development is immense. Optical computers, with their ability to process information at unprecedented speeds, could revolutionise fields like artificial intelligence, machine learning, and scientific simulations. The research team's work brings us closer to this exciting future.
Further information:
Denis A. Sannikov et al, Room temperature, cascadable, all-optical polariton universal gates, *Nature Communications
(2024). DOI: 10.1038/s41467-024-49690-3
Provided by: Skolkovo Institute of Science and Technology