Laser photonics in the Terahertz range getting closer to reality

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Laser Sound
First take the case of light: you turn a generator of photons, best known as a lamp and the light spreads in all directions. But if you drive a special generator of photons, best known as a laser , you have photons neatly following a precise direction.
Now for the sound: you turn a speaker, and the probes sonorous will spread from him following his design in all directions.
Full stop. Here there is, of course, a gap: there is not a “form laser” sounds, whose waves come out perfectly directed and concentrated.
Laser phononics
But this is about to change. Two groups of physicists, one U.S. and one from the UK, working separately, simultaneously announced progress towards the development of lasers phononics – devices capable of emitting sounds the same way that lasers emit optical light.
When completed, this development will produce new kinds of devices, high-resolution imaging, and several other medical and industrial applications, such as the ability to transfer large powerdistance in concentrated form.
As the laser optics were incorporated in many devices that are already part of everyday people, a laser sound will be the key to a range of applications yet unimagined.
Similarities between sound and light
Light and sound are similar in many respects: both can be thought of in terms of waves and both come in units of quantum mechanics, or quanta – photons in the case of light and phonons in the case of sound.
In addition, both the light and the sound can be produced as random collections of quanta – as in the case of a lamp – or as wave packets traveling in a coordinated manner – as is the case of laser light.
Think, for example, the similarities between optical microscopes and acoustic microscopes, including sonar and radar, and see that there are indeed many similarities.
In terms of classical physics, this is because the same wave equations governing the oscillations of atoms, ions and molecules in a sound wave, and the oscillation of electric and magnetic fields in a light wave.
And in terms of quantum physics, basic quanta of light (photons) and sound (phonons) follow the same rules that describe all the particles with integer spin bosons.
Many physicists believe that these parallels imply that lasers need to be as viable as they are sound to light.
Terahertz waves
While low-frequency sounds in the range that humans can hear (up to 20kilohertz), are easy to produce both random and ordered, things get more complicated in the range of terahertz (trillion hertz) – is in this range super high frequencies which are the potential applications of lasers phononics.
The problem is that sound travels much more slowly than light, which means that the wavelength of the sound is much smaller than that of light in a certain frequency. With this, the tiny structures that produce waves in the terahertz range, instead of generating a laser phononics orderly and consistent, tend to emit phonons randomly.
Towards laser sound
The group of scientists at the California Institute of Technology (Caltech), USA, overcame this problem by mounting a pair of microscopic holes that allow only the emission of specific frequencies of phonons. They also set the system so that it is capable of emitting phonons of different frequencies, which is done by changing the distance between wells.
But the British group, Nottingham University, took a different approach. They built their device with electrons moving through a series of structures known as quantum wells. As an electron jumps from one quantum well to the next, it produces a phonon.
Until now, the Nottingham group has not shown a true generation of a laser sound, but your system amplifies high frequency sounds in a way that suggests that the device could become the main component of a future laser phonon.
Uses of lasers sound
Albert Einstein predicted in 1917 the possibility of matter emit photons consistent, always with the same frequency and phase. It was what he called “stimulated emission”. The laser was demonstrated in practice over 40 years later, in 1960.
Since then, the phonon laser has occupied the minds of many researchers. How long before it becomes practical is a difficult question to answer.
It is a fact that the laser sound is not ready yet. But definitely take the two developments to emit sound waves in a coherent and ordered the field of theoretical possibilities, putting the laser on the agenda of sound achievements in the near future.
Meanwhile, physicists have begun to work out the possibilities of using new technology, including non-ionizing medical imaging (without radiation from X-rays, for example), devices of high precision measurement, high-energy concentrates sounds – in short, everything that the lasers will have a sound future as bright as the light lasers.