A barium titanate crystal is like a crowd where everyone holds a pointer. Normally, the pointers face in random directions, but when you apply an electric field, they all snap to point the same way. This ordered state is called ferroelectric: it stores information the way a compass needle stores direction.
Until now, the consensus was that flipping all the pointers quickly required a special trick: hitting the resonance of the crowd's own vibrations — the so-called phonons. It's like pushing a swing in rhythm to make it go higher. But the authors tried a different approach: they shone far-infrared pulses with wavelengths of 35–60 micrometers — tens of times thinner than a human hair. And it turned out that the switching happens not because of resonance, but simply because the crystal absorbs light and heats up in the right places.
The big surprise is that switching works across a wide range of frequencies, not just in narrow resonant windows. This means that for ultrafast writing in ferroelectric memory, you don't need to precisely tune the laser to a specific material. Just heat the crystal with a short pulse, and the pointers flip on their own.
The practical payoff could be huge: ferroelectrics are already used in memory cards and sensors, and now there's a way to switch them in picoseconds — trillionths of a second. That's faster than the blink of an eye and on par with the speed of the fastest transistors.
Barium titanate is the very material used to make capacitors in most electronic devices, from phones to cars.
In Star Trek, alien computers store data in crystals that change structure under light — very much like what happens in this experiment.