Extreme control over mechanical waves opens the door to new technologies
At the CUNY Graduate Center, a team of physicists has borrowed an insight from the quantum world of electronics and applied it to the ancient problem of controlling sound. By rotating precisely engineered material layers against one another, they have discovered that mechanical waves — the vibrations underlying ultrasound, sensing, and signal processing — can be steered, focused, and reconfigured without rebuilding the device that carries them. The discovery, named twistelastics, suggests that the rigid, single-purpose designs long governing these technologies may give way to systems as adaptable as the problems they are asked to solve.
- Technologies like ultrasound imaging and signal processors have long been locked into fixed designs, unable to adapt once built — a fundamental constraint that limits their versatility.
- CUNY researchers found that stacking two identical engineered surfaces and rotating one against the other fundamentally rewrites how vibrations travel through the combined structure.
- At precise 'magic angles,' waves stop spreading freely and instead become tightly focused along specific paths, enabling faster, more efficient signal processing across a broad range of frequencies.
- The technique also makes devices more forgiving — systems built on twistelastics principles resist the manufacturing imperfections that typically degrade performance.
- The field is now oriented toward a future where a single physical device can be retuned by adjusting an angle rather than replaced, transforming ultrasound machines, sensors, and communication systems alike.
Researchers at the Advanced Science Research Center of the CUNY Graduate Center have introduced a technique called twistelastics, detailed in the Proceedings of the National Academy of Sciences, that gives engineers unprecedented control over how sound and mechanical vibrations move through materials. The method adapts twistronics — a concept from electronics — to the physical world of waves, using the rotation between two layers of engineered surfaces to reshape wave behavior on demand.
The team, led by physicist Andrea Alù, combined mathematical theory, computer modeling, and hands-on fabrication to develop the approach. They 3D-printed metasurfaces patterned with microscopic pillars, then stacked and rotated identical pairs against each other. The rotation alters the underlying topology governing wave travel, and at a specific "magic angle," vibrations become tightly focused and guided along defined paths — conditions that accelerate signal processing and enable control across a wide spectrum of frequencies.
The practical stakes are considerable. Ultrasound imaging, microelectronic sensors, and signal detection systems all depend on managing vibrations, and until now those systems have been built for fixed purposes. Twistelastics changes that: the same device can be retuned simply by adjusting the angle of rotation, without rebuilding it. The technique also confers resilience — systems designed this way perform reliably even when manufacturing is imperfect. The research points toward a generation of imaging, sensing, and communication devices that are no longer static tools but reconfigurable instruments.
A team of researchers at the Advanced Science Research Center of the CUNY Graduate Center has found a way to steer sound and vibrations through a borrowed concept from the world of electronics. Their discovery, detailed in the Proceedings of the National Academy of Sciences, introduces what they call "twistelastics"—a method that harnesses tiny rotations between layers of precisely engineered surfaces to direct how mechanical waves move and behave.
The practical applications are substantial. Ultrasound imaging, the sensors embedded in microelectronics, and systems designed to detect and process signals all depend on controlling sound and vibration. Until now, these technologies have relied on fixed designs that offer little room for adjustment once built. The new approach changes that equation. By rotating two layers of engineered material relative to each other, engineers can now reconfigure how waves travel through a system, adapting it to different tasks without rebuilding it from scratch.
Andrea Alù, a physicist at the CUNY Graduate Center and founding director of the Photonics Initiative at the research center, described the implications plainly: rotating these two layers gives scientists "extreme control over mechanical waves," he said, and that control opens possibilities for sensing systems, communication technologies, and signal processing that were not feasible before.
The team's path to this discovery combined three approaches: mathematical theory, computer modeling, and hands-on experimentation. They designed special surfaces called metasurfaces, which they patterned with microscopic pillars, then fabricated them using 3D printing. When two identical metasurfaces are stacked and twisted at different angles to each other, the combined structure fundamentally changes how vibrations spread through it. The rotation shifts the underlying topology that governs which direction waves travel. At a particular rotation angle—which the researchers call the "magic angle"—waves become tightly focused and guided along specific paths, creating conditions for faster and more efficient signal processing.
The implications ripple outward. Twistelastics allows for control of broadband signals across a wide spectrum of frequencies, and it enables wave behavior to be adjusted quickly, which means information can be transmitted more effectively. The technique also promises to make systems more robust. Manufacturing imperfections are inevitable in any fabrication process, but systems designed using twistelastics principles show greater resistance to these glitches, meaning they perform more reliably even when they are not built perfectly.
What makes this work significant is the shift it represents: from static, one-purpose designs to dynamic, reconfigurable systems. The same physical device can now be tuned to handle different frequencies, different signal types, different sensing tasks—simply by adjusting the angle of rotation. That flexibility, combined with the precision that the "magic angle" effect provides, suggests that ultrasound machines, sensors, and signal processors built on these principles could be more capable and more adaptable than their predecessors. The research points toward a future where the devices we rely on for imaging, communication, and detection are no longer locked into a single mode of operation but can be reshaped, electronically or mechanically, to meet changing demands.
Citas Notables
By simply twisting these two layers, we can achieve extreme control over mechanical waves. This opens the door to new technologies for sensing, communication, and signal processing.— Andrea Alù, Einstein and Distinguished Professor of Physics at CUNY Graduate Center
La Conversación del Hearth Otra perspectiva de la historia
So this idea of twistelastics—it's borrowed from twistronics in electronics. What was the original insight that made someone think, "Wait, this might work for sound too"?
The core insight is that rotation itself is a kind of control knob. In electronics, when you twist graphene layers at specific angles, you unlock new electrical properties. The CUNY team asked: what if we apply that same principle to mechanical waves? The answer turned out to be yes, but the engineering required designing surfaces with the right microscopic structure to respond to that twist.
And this "magic angle" they mention—is that a fixed number, or does it change depending on what you're trying to do?
It's a fixed number for a given design of metasurface, but different metasurface patterns would have different magic angles. So you design your surfaces first, then you know what angle to rotate them to. It's not magic in the mystical sense—it's a precise mathematical property of the structure.
Why does this matter more than just building a better fixed device?
Because you can't predict every use case when you manufacture something. With a fixed design, you're locked in. With twistelastics, the same physical device becomes adaptable. You can adjust it for different frequencies, different signal types. That's enormous for something like ultrasound imaging, where you might need different settings for different tissues or different diagnostic questions.
What about the manufacturing angle you mentioned—the resistance to imperfections?
That's the practical win. Real manufacturing is messy. Tiny variations happen. Traditional designs are fragile to those variations. But systems built on twistelastics principles are more forgiving. They still work well even when they're not perfect, which means lower costs and higher reliability in the field.
So this is still early research, or is there a path to actual devices?
They've built 3D-printed prototypes and tested them. The theory is solid, the simulations match the experiments. The next step is scaling and optimizing for specific applications—ultrasound machines, sensors, communication systems. That's engineering work, but the hard part, the discovery, is done.