An international team of scientists has taken a decisive step toward faster, more energy-efficient artificial intelligence and data processing in general with the discovery of luminescent nanocrystals that can quickly switch between glowing and off states. This opens up the possibility of computing literally at the speed of light, abandoning electrons and switching to the use of photons in microcircuits.
Image source: AI generation Kandinsky 3.1/3DNews
«The exceptional switching and memory capabilities of these nanocrystals could one day become integral to optical computing, a way to quickly process and store information using the lightest particles that move the fastest in the universe,” said Artiom Skripka, assistant professor in the College of Science at Oregon State University. The research work was published on January 3, 2025 in the journal Nature Photonics.
The study examines the capabilities of nanoparticles with avalanche-like characteristics. Such materials exhibit extremely nonlinear properties, in particular light-emitting properties. A small increase in the power of the exciting radiation can significantly increase the intensity of their own glow. This can be used to save energy on the operation of circuits – it is enough to bring nanoparticles to a state close to avalanche-like excitation and then work with only small portions of energy for the excitation source.
The researchers studied nanocrystals consisting of potassium, chlorine and lead and doped with neodymium. KPb2Cl5 nanocrystals themselves do not interact with light. When combined with neodymium, the material begins to effectively process light signals, making it useful for optoelectronics, laser technologies and other optical solutions.
«Typically, luminescent materials emit light when they are exposed to a laser, but remain dark when they are not, Skrypka said. “On the contrary, we were surprised to discover that our nanocrystals lead parallel lives. Under certain conditions, they exhibit a peculiar behavior: they can be both bright and dark at exactly the same laser wavelength and power.”
This behavior is called intrinsic optical bistability. The inherent optical bistability of nanocrystals is a step forward toward photonic integrated circuits that can outperform current electronic and optoelectronic systems and have greater efficiency.
Image source: Artiom Skripka, OSU College of Science
«If the crystals are initially dark, we need higher laser power to turn them on and observe the emission, but once they start emitting, we can observe their emission at lower laser power than we needed to turn them on initially, says Skripka. “It’s like riding a bicycle—you have to push hard on the pedals to get it moving, but once it starts moving, you need less effort to move.” And their glow can be turned on and off really abruptly, as if by pressing a button.”
The transition to optical signals promises to significantly reduce the consumption of photonic computing platforms wherever they are used. It is also the path to new applications in medicine, sensors and many other areas. But the research stage is not yet completed. It will take a lot of work to get it to commercial products.