Deep in a laboratory at Eindhoven University of Technology, energy is now jumping between particles over distances that scientists once thought impossible. Professor Jaime Gómez Rivas and his team—postdoctoral researcher Jie Ji and graduate researcher Wouter Holman—have just extended a fundamental limit on energy transfer by roughly 200,000 times, pushing it from nanometers to millimeters using a deceptively simple tool: vibrations in microscopic gold rods.
The breakthrough matters because it solves a problem that has haunted physics for decades. Normally, when a molecule absorbs energy, it bleeds that energy back out as waste heat or light, like a leaky bucket. But there's a rare exception called Förster resonance energy transfer, or FRET, where energy jumps directly from one molecule to another through an invisible interaction between their electric fields—no heat, no photons, just a perfect handoff. Plants use FRET during photosynthesis, channeling captured sunlight to cells where it becomes food without losing a joule along the way. Scientists have learned to weaponize FRET too, using it as a precision instrument to measure how close two molecules sit to each other, crucial for studying proteins or detecting disease markers in blood and tissue.
The catch has always been distance. FRET only worked across nanometers—about ten thousand times thinner than a human hair. For decades, it seemed a hard limit written into the laws of physics. Until now. The TU/e team managed to extend the effective range to several millimeters, a leap so vast that Gómez Rivas likens it to a person jumping 200 kilometers from Amsterdam to Brussels. In the world of molecules, it's epoch-making.
The secret lay in harnessing a phenomenon called bound states in the continuum, or BICs—electromagnetic waves that, through a precise cancellation effect, become completely trapped on a surface. They radiate no energy outward. They're present but invisible, and they persist with remarkable durability. The researchers built a flat glass surface studded with microscopically small gold rods arranged in an exquisitely precise pattern. When a measurement probe touched the surface at exactly the right frequency, it triggered a BIC state that transported energy without radiation to a detection probe placed 2 millimeters away—no energy spilled, all delivered.
What happens is this: the gold rods vibrate and resonate, carrying energy across the surface. Normally, such resonances emit photons into the surrounding environment, making energy transfer inefficient. But BICs keep the energy completely confined to the surface, achieving the same lossless transfer that FRET manages, only over distances previously thought impossible. Even more striking is the directionality. Along one axis, energy travels effortlessly for the full two millimeters. Along the perpendicular direction, it fades after only a fraction of that distance. This built-in preference for a single direction could become a tool in future devices to control energy flow, much as electrical circuits direct current.
What makes the result particularly elegant is that it happens on a flat surface at room temperature, with no optical waveguides needed. The team published their findings in Science Advances, and the implications ripple outward: quantum communication, more efficient solar energy harvesting, ultrasensitive medical sensors. The fundamental limit hasn't just been pushed—it's been reimagined entirely.