The power of using special light-based technologies has long been promised a stable and effective way to control how light moves through devices. However, one major limitation is the need for slow and careful changes to maintain so-called “insulating” conditions, in which light moves through the system without unpredictability between different energy levels. A recent study provides important advances by determining the shortest time that these changes may occur, opening the door to smaller, faster optics.
Professor Tao Li and Wange Dr. Song of Nanjing University have developed a light-guided structure that uses a specially designed light-guided structure that is a specially designed light-guided structure used on high-performance optics to achieve the method of reaching this shortest limit (called the shortest, shortest time or length of insulation). Their work was published in the peer-reviewed Nature Communications.
The research focuses on a process called topological pumping, a method of transferring light or other particles from one position to another by carefully adjusting conditions over time. What makes this process unique is its topological nature – meaning it relies on the overall structure of the system, not its specific details, and it helps it stay stable even if there is imperfection. Typically, this transfer requires slow adjustments to keep the system adiabatic, but the team discovers a way to speed up the process by optimizing the path to how the control system develops.
To accomplish this work, Professor Li and Dr. Song focused on what is called the shape of the modulation cycle, i.e. the path changes of key system properties to guide light. The core of their approach is to minimize berry connections, a mathematical concept that describes how the quantum state of light moves as it moves in a system. This connection determines the possibility that light enters an unwanted state. By finding a way to reduce paths, researchers have enabled the system to evolve faster while remaining stable.
The team tested this with two versions of its design, both based on the Rice-Mele model, a simplified framework that is often used to study two alternating parts (such as optical waveguide chains). One design follows a traditional loop, while the other uses its optimized version, called the INFI loop (the short for “iNVimum” – which represents the most efficient route. In a standard setup, the light is clean only when the device is relatively long. In contrast, the INFI loop achieves the same result over a short distance. Professor Li said: “We approach the adiabatic quota by minimizing effective berry connections along the loop.
These results are not just theoretical. The researchers built the device on chip using thin layers of Nibet lithium, called the film-Niobate-niobate-in-unsulator platform, a technology that combines good optical properties with the ability to make compact devices. They inject light into the waveguide structure – small paths that can cause light along a specific route to guide the light and observe how it moves. In traditional designs, light cannot stay on track unless the path is long enough. But in the new design, the light follows its predetermined route and is shorter in length, confirming the success of the method.
Dr. Song added: “The highest amount of adiabatic accelerates the topological pump from the limitations of slow evolution and promotes the design of compact topological equipment.” In other words, this approach removes the limitations due to slow processes and makes devices with the same performance smaller. This is especially important for Niobate lithium platforms, which usually require more space because the material bends less light than other spaces such as silicon.
These findings also provide a new understanding of how to control light in systems that are targeted at flaw stability. By rethinking the shape of the paths in the system configuration space – representing the abstract landscape of all possible settings – the team showed that light can be pumped faster without losing reliability. This has broad potential in fields such as quantum computing, where light needs to move accurately, quickly, or in telecommunications and sensing technologies that require compact, reliable optical circuits.
The research of Dr. Li and Song not only improves the performance of these devices, but also provides new insights into the physics behind them. By reaching the adiabatic, they have shown how careful designs can push the limits of speed and efficiency in light-based systems, a step forward in developing next-generation optical technologies.
Journal Reference
Wu S., Song W., Sun J., Li J., Lin Z., Liu X., Zhu S., Li T. “The insulation quota of topological pumps close to thin-film lithium lithium liquefied liquid.” Nature Communications, 2024. doi: https://doi.org/10.1038/s41467-024-54065-9
About the Author
Li Li He is a professor at Nanjing University. He received the National Science Foundation from the Foundation for Outstanding Young Scholars and Outstanding Young Scientists. He also received the “Wang Kuancheng” education fund from Hong Kong and was selected as a leading talent in science and technology innovation by the Ministry of Science and Technology, and became the first group of “Dengfeng Project B” at Nanjing University. He is recognized five times for his significant progress in the field of optics in China. Professor Li delivered more than 50 invited talks at international conferences and published more than 130 papers in journals such as Nature and its Sub-Journal. Rev. Lett. and Light Sci. Apply, his work has been cited more than 12,000 times. Currently, he is a member of the Youth Editorial Committee of China Laser Publishing House and a member of several other journals and publications, including Science Bulletin and ADI. He is also a member of the board of directors of the China Society of Materials Research, Jiangsu Sports Society and Jiangsu Optical Society.
Wange Song He is an associate researcher at Nanjing University and a visiting scholar at the University of Hong Kong. He received his bachelor’s degree and doctorate in materials physics from Nanjing University in 2016. He received his optical engineering major from the same university in 2021. Song’s research focuses on micro-nanooptics, and in recent years he has made significant contributions in the fields of topological optics and non-Hollow optical field operations. To date, he has published more than 30 papers in international academic journals, such as PRL (6 papers), Nat. Community and science. ADV. His research has been introduced in editorial advice and covered articles and is highlighted by Physics, Physorg and Spie. He also serves as a member of the Youth Editorial Board and a guest editor for several academic journals.
