ITMO University scientists, working with colleagues from multiple institutions, report capturing ultrafast hybrid light particles previously considered impossible to trap. The team used a femtosecond laser and a microscopic pattern etched onto a thin perovskite film to overcome the limitations of the Klein paradox, a challenge hindering the development of optical computing.
“We made a film that’s 1,000 times thinner than a human hair and etched a microscopic lattice right onto it, all to make the interaction of light and matter as effective as possible,” explains Sergey Makarov, head of ITMO’s Institute of Photonics. This advance, published in Science Advances, aims to create optical devices capable of self-retraining and exceeding the efficiency of current electronics.
Perovskite Metasurfaces Enable Ultrafast, Energy-Efficient Optical Computing
The ability to contain exciton-polaritons, hybrid light-matter particles, within a microscopic trap represents a step toward realizing practical optical computing. Researchers directed an ultrashort laser pulse at a minuscule dot etched onto the film, creating localized conditions that prevented the polaritons from scattering and allowing for their stable confinement. This control over light propagation circumvents the limitations imposed by the Klein paradox, a phenomenon that previously hindered the trapping of nearly massless particles essential for optical signal processing.
Perovskite’s unique material properties made this breakthrough possible; it is both easier and less expensive to manipulate than conventional semiconductors used in photonics. The resulting film exhibits quantum effects at room temperature, a departure from previous experiments requiring ultralow temperatures.
Confirmation of successful polariton capture came through spectroscopic analysis; researchers observed that the trapped particles separated into distinct energy groups, manifesting as different colored beams of light upon exiting the perovskite film. This separation demonstrates that the polaritons were not simply scattering randomly, but were instead confined within the trap and adopting specific, defined states.
Anton Nalitov, the study’s main theorist and a leading researcher at MIPT, described the process as creating “a genie and immediately trapped it in a bottle,” highlighting the balance between energy influx and loss that allows them to bypass the Klein paradox. The implications of this work extend beyond fundamental physics, promising a pathway toward dramatically more efficient computing architectures.
Current electronic processors rely on the movement of electrons, generating significant heat as a byproduct; optical computers, in contrast, would use light to perform calculations, minimizing energy consumption. “Neural networks and AI models require a great deal of computing power, while regular processors use up too much energy that’s then converted into heat,” explains Makarov.
“Metasurfaces like ours can complete such tasks directly via light: whereas in regular computers electrons move along wires between transistors and memory and warm up the chip, in our case light will pass through the structure within fractions of a nanosecond and carry out complex computations with minimal energy spending.” The team’s future work focuses on integrating these perovskite metasurfaces into diffractive neural networks, optical systems where light performs computations by passing through microscopically patterned layers.
A key goal is to create a compact chip, approximately one square centimeter in size, populated with numerous “traps” capable of performing complex operations like matrix-vector multiplication. Such a device could accelerate large language models, improve image recognition, optimize logistics, and enhance fraud detection systems. According to the researchers, this technology has the potential to make computations hundreds of times faster and more energy-efficient than current electronic systems.
The study, supported by the national program Priority 2030 within ITMO University’s strategic focus on photonic computing, represents an advance in the development of computing technologies. Makarov stated, outlining the potential scale of this innovation.
Metasurfaces like ours can complete such tasks directly via light: whereas in regular computers electrons move along wires between transistors and memory and warm up the chip, in our case light will pass through the structure within fractions of a nanosecond and carry out complex computations with minimal energy spending.
Sergey Makarov, the head of ITMO’s Institute of Photonics and the chief researcher at the Faculty of Physics
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