Light Trap: Holding the Elusive ⚡ экспресс
Researchers have achieved a breakthrough in integrated quantum memory, reaching record storage efficiency: 80.3% for weak laser pulses and 69.8% for single photons. The core is crystals doped with rare-earth ions (Eu3+:Y2SiO5) placed inside optical microresonators with matched impedance. Two designs were used: thin membranes and waveguides sculpted by femtosecond lasers. The device can also hold up to 20 temporal modes at once. The most surprising feature is the ability to spectrally tune the memory by simply stretching the crystal—much like changing the pitch of a guitar string. This opens the door to scalable quantum repeaters and chips.
For quantum internet, light needs to be delayed—like mail at a sorting center. At the core is a thin crystal plate with europium ions (the element that gives red glow to smartphone screens). Placed between two mirrors, the crystal forms a trap. Light, ricocheting inside, is absorbed by an ion and emitted back a moment later—just like a mailbox that accepts and returns letters.
Thanks to spectroscopy, ideal materials were selected. Efficiency: 80% for laser pulses and nearly 70% for single photons from optical fiber. According to the Standard Model, light always travels at the speed of light, but here it freezes.
A thin membrane allows tuning the color of captured light with a gentle press—like a mailbox with an adjustable slot. This builds on the single-photon experiments of Serge Haroche and Jeff Kimble, now embodied in chips for quantum repeaters and optical processors.
🎯 A crystal with europium ions can store a light pulse for longer than a millisecond—by quantum standards, that's an eternity, during which light would circle the Earth more than seven times.