Technology
Most powerful sounding laser ever made
Sound lasers use sound waves (phonons) instead of light waves (photons). These phonon lasers promise advances in medical imaging, deep-sea exploration, and many other areas.
Guangzong Xiao and colleagues at Hunan Normal University in China have now developed a technique that gives phonons an electronic nudge, a small boost but enough to dramatically increase the power and precision of the sound waves produced by the laser.
Until now, phonon lasers have relied only on weak, imprecise sound waves, limiting their usefulness. The new method overcomes this difficulty by essentially "locking" the sound waves in a more stable state, which allows the use of stronger waves.
Although phonons are commonly said to be the "particles" of sound, they are not true particles but collective vibrations of atoms in a crystalline structure. And these vibrations, which are pressure waves, can be quantized as if they were particles.
Thus, it is easy to see that a sound laser is essentially a "mechanical laser", or a mechanical analogue of an optical laser. The most efficient technique for building them is based on microspheres kept in levitation, and then shaken without contact so that their movement generates sound waves.
Due to the complexity of the device, the power of the sound laser is still in the range of milliwatts (maximum 50 mW), but the team believes that it is enough to think about practical applications.
"This work, which provides much stronger and better quality signals from coherent phonon harmonics, is a fundamental step toward controlling and utilizing nonlinear phonon lasers for applications such as phonon frequency combs, broadband phonon sensors, and diagnostics." biomedical ultrasonic technology," the researchers concluded.