Humans were first able to produce lasers with light in the 1960’s, and this invention has helped to revolutionize many different aspects of life from medical technology to manufacturing. These powerful beams of light have many practical applications and can be made both weak enough to be a toy or powerful enough to cut through strong materials.
A team of physicists has recently published a paper that shows that the next major advancement in laser technology might not use light at all. Instead, it would use sound.
Light lasers work by producing light waves that are all at nearly the same wavelength so they are said to be in phase. This allows the beam of light to be very narrow and bright.
The physicists are looking at ways to create sound lasers by manipulating the phonons that make it up.
This is explained by Professor of Molecular Engineering Innovation and Enterprise at the University of Chicago Pritzker School of Molecular Engineering, Andrew N. Cleland, in a piece he wrote for The Conversation:
“Similar to the photons that make up beams of light, indivisible quantum particles called phonons make up a beam of sound. These particles emerge from the collective motion of quadrillions of atoms, much as a ‘stadium wave’ in a sports arena is due to the motion of thousands of individual fans. When you listen to a song, you’re hearing a stream of these very small quantum particles. Originally conceived to explain the heat capacities of solids, phonons are predicted to obey the same rules of quantum mechanics as photons. The technology to generate and detect individual phonons has, however, lagged behind that for photons.”
In the study, which is published in the journal eLight, scientists had an extremely small ball of silicon oxide (SiO2) that was suspended by beams of light. The beams of light vibrated the ball so that it had an internal sound. The sound was a high-pitched beep.
From there, they started to manipulate the vibrating by using an alternating electric field, which causes a resonance. That amplified the sound that was being produced by up to one thousandfold.
In the paper, this was explained by the team:
“By applying a single-colour electronic injection to this levitated system, giant enhancement can be achieved for all higher-order phonon harmonics, with more than 3 orders enhanced brightness and 5 orders narrowed linewidth.”
The work in this area is still early, but there is large potential uses for it once perfected. The team explains:
“This work, providing much stronger and better-quality signals of coherent phonon harmonics is a key step towards controlling and utilizing nonlinear phonon lasers for applications such as phonon frequency combs, broadband phonon sensors, and ultrasonic bio-medical diagnosis.”
To learn more about this potentially important advancement, consider watching this video:
I can’t wait to see what they will do with sound lasers.
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