A Diamond Speck Becomes a Sound Laser ⚡ экспресс
In a levitating nanodiamond with a single NV center (nitrogen-vacancy), physicists have created a phonon maser — a device that amplifies mechanical vibrations, much like a laser. By exciting the defect's spin with microwaves and light, they inverted the population of its states, turning the center into an amplifying medium for the motion of the entire particle. The self-oscillation threshold turned out to be record-low: just a few percent inversion is enough, and the gain can outpace losses by orders of magnitude. Simulations confirmed stable coherent oscillation with phase diffusion, following Maxwell–Bloch equations — just like in a conventional laser.
A diamond dust particle made of carbon floats in a vacuum on a laser beam. Inside there is a defect: a nitrogen atom next to a vacancy. Under the influence of light and microwaves, it starts to jitter, rocking the entire particle. This is how a sound laser starts: weak random nudges turn into a powerful steady hum. The mechanism echoes the idea of Charles Townes, who built the maser for microwaves, but here sound vibrations are amplified. All it takes is a tiny excess of excited states — just a couple of percent.
The calculations fully match the laws of quantum optics. Such a system can detect gravitational waves or the force of impact from a single molecule. And, perhaps for the first time, it will let us see quantum effects — such as the simultaneous existence of two opposite vibrations — in an object visible to the naked eye.
🎯 The maser is the older brother of the laser: it was first built in 1954 for microwaves, and now the same principle brings sound vibrations to life in a crystal.
🎬 In science fiction, self-exciting crystals often serve as the heart of detectors and engines.