(Nanowerk Spotlight) The ability to precisely control the flow of light is critical for technologies like high-speed data transfer, advanced computing, and telecommunications. Yet, despite the promise of photonics, existing systems remain rigid and impractical for large-scale use. Current photonic designs are either fixed in their function or rely on expensive, energy-intensive processes to adapt, making them unsuitable for the flexible demands of real-world applications. This limitation has slowed progress in the development of practical photonic networks, keeping them from reaching their full potential.
Recent research, however, has introduced a new approach that could reshape the future of photonics. A team of scientists at Southeast University in Nanjing, China, has developed phase-transition photonic bricks – modular, reconfigurable units that offer the flexibility and scalability lacking in today’s systems. These bricks function as customizable building blocks for photonic networks, allowing light to be routed and re-routed as needed with minimal energy input and far lower production costs than existing systems.
At the core of this innovation is the ability of photonic bricks to switch between different configurations, creating adaptable pathways for light. This is achieved through mechanical rotation, which alters the photonic properties of each brick without the need for electrical or optical tuning. In essence, these bricks can act like digital switches, flipping between two states—referred to as “Brick 0” and “Brick 1”—to control how light moves through the system. By arranging these bricks into specific patterns, researchers can create topologically protected pathways that guide light with precision, even in the presence of defects or imperfections.
The reprogrammable topological photonic insulator (RTPI) is composed of reusable photonic bricks. a) Each reusable lattice can be rotated to implement the phase transition between binary coding states, namely photon bricks “0” and “1”. By assembling photon bricks into a topological photonic insulator, a reconfigurable light propagation highway can be formed along the domain-wall interface, which can be demonstrated by the corresponding energy band diagrams. b) Reconfigurable and programmable properties of RTPI. c) Reusable and deformable properties of RTPI. (Image: Reproduced from DOI:10.1002/adfm.202408727 by Wiley-VCH Verlag)
One of the major advantages of these phase-transition photonic bricks is their energy efficiency. Traditional systems that rely on electrical modulation require continuous power to maintain their configurations, consuming large amounts of energy even when not actively being reconfigured.
In contrast, photonic bricks only require energy during the moment of reconfiguration. Once a new configuration is set, the system remains stable without further power input. This drastically reduces energy consumption, making photonic bricks an attractive option for large-scale applications like data centers or telecommunications networks, where energy efficiency is a critical factor.
In addition to their energy efficiency, photonic bricks offer significant cost savings in fabrication. Current reconfigurable photonic systems often require complex electronic components, such as diodes or varactors, that drive up both the production and operational costs. Photonic bricks, on the other hand, are mechanically modulated, meaning they can be manufactured more simply and at a fraction of the cost. This opens the door to wider adoption of photonic technologies, as the economic barrier to entry is significantly lowered.
The team behind this research demonstrated the potential of photonic bricks through a series of experiments. Using a lattice of these bricks, they constructed reconfigurable pathways for light and observed robust, scatter-free propagation, even through sharp bends and irregular pathways. This resilience is a key feature of topological photonics, where light remains protected from disruptions as it travels along the edges of the material. In their experiments, the researchers were able to shift between different light pathways simply by rotating the photonic bricks, proving the flexibility and adaptability of their design.
These bricks are not only reconfigurable but also scalable. The modular nature of the system allows for networks of photonic bricks to be assembled, disassembled, and reassembled in different configurations, adapting to new tasks or environmental conditions. This scalability makes photonic bricks a versatile tool for a range of applications, from telecommunications to computing and even quantum technologies, where dynamic control of light is essential. Whether used in large data centers or in smaller, specialized systems, the ability to customize and reconfigure light pathways on demand offers new possibilities for photonics that were previously out of reach.
Perhaps one of the most exciting aspects of this innovation is its sustainability. The bricks are designed to be reusable and recyclable, a rarity in the world of advanced photonics where many components are fixed and discarded after use. This ability to reconfigure and reuse the same units over and over aligns with growing demands for more sustainable technological solutions, making photonic bricks not only a functional innovation but also an environmentally conscious one.
There are still challenges ahead. Currently, the system relies on manual assembly, which can be time-consuming and labor-intensive, especially when scaling up to larger networks. Future developments could focus on automating the assembly process, potentially using robotic systems to arrange and reconfigure the bricks more efficiently. Moreover, while the bricks work well at microwave frequencies, further advancements in fabrication techniques will be needed to adapt the system to operate at higher, optical frequencies, where many practical applications lie.
Nonetheless, phase-transition photonic bricks represent a significant step forward in the evolution of photonic systems. By combining flexibility, scalability, and cost-effectiveness, these bricks offer a practical solution to the long-standing challenges in the field. As the technology matures, it has the potential to transform a wide range of industries that rely on precise, energy-efficient light manipulation, from telecommunications and computing to quantum technologies and beyond.
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