SMART NEWS

Scientists Build a Phaser, a New Kind of Sound-Laser

A laser that shoots sound, a Star Trek fantasy that’s nearly within reach

March 19, 2013

Imran Mahboob just made an entire generation of Trekkies happy. In a new study, Mahboob and colleagues lay out their production of a real working phaser, a device that can produce a concentrated pulse of high frequency sound waves. Basically, the scientists made a laser that used sound instead of light. Wired:

In traditional lasers, a bunch of electrons in a gas or crystal are excited all at the same time. When they relax back to their lower energy state, they release a specific wavelength of light, which is then directed with mirrors to produce a beam.

Sound lasers work on a similar principle. For Mahboob and his team’s phaser, a mechanical oscillator jiggles and excites a bunch of phonons, which relax and release their energy back into the device. The confined energy causes the phaser to vibrate at its fundamental frequency but with at a very narrow wavelength. The sound laser produces phonons at 170 kilohertz, far above human hearing range, which peters out around 20 kilohertz.

The thing that makes the phaser so special is not that the sound waves are particularly strong or high energy, but that they’re super pure in their emitted frequencies, which produces a “spectrally pure” sound emission, says Physical Review Letters. Also, though a phaser has been built before, back in 2010, that one used a laser to make the sound waves. This new phaser skips the laser step and produces to pure tone with a nanoscale drum, says Wired.

For now, says Wired‘s Adam Mann, the phaser’s usefulness is limited, because as soon as the phaser beam leaves the device it also loses its purity. How the phaser evolves is to be determined, but the researchers see it mostly being useful for such boring things as medical imaging and computing, says Wired. Elsewhere, however, engineers are still hard at working turning sound into a weapon.