Sound amplification by stimulated emission of radiation

Saser is an acronym of Sound Amplification by Stimulated Emission of Radiation (Sound Amplification by Stimulated Emission of Radiation ). Here an incident sound wave is amplified by an active medium, so that coherent sound waves generated in a confined space area. The Saser is therefore the acoustic counterpart of the laser.

Development

The idea of ​​a laser for analog amplification of the sound is pursued by various research groups for several years. The main differences of the individual batches were mainly in the active medium used in the amplification of the sound.

For the first time the viability of a SASERs of the Belarusian physicists IV Volkov, ST Zavtrak, and proved IS kuten mid-90s of the 20th century at the Institute of Nuclear Problems in Minsk. They use liquids with gas bubbles as the active medium and a changing electric field to pump. This work they submitted on 15 January 1997, the American Physical Society, which she published in issue 56 of the Physical Review.

On 2 June 2006, the Englishman Anthony Kent published ( University of Nottingham ) and the Ukrainians Borys Glavin ( Lashkarev Institute of Semiconductor Physics) their work in Physical Review Letters. Above all, the simple structure of the gain medium is noteworthy because it only consists of thin semiconductor layers.

Operation

The basic principle is no different within the ASER - family (lasers, masers, Saser ). Meet Incident waves on an active medium in which they freely translated more waves due to stimulated emission. Unlike masers and lasers, which are based on electromagnetic waves or photons, is the Saser to sound waves or phonons. The individual members of the ASER family also differ in the frequencies of the radiation used. As a laser operates at frequencies between 10 to 1 THz PHC, a grain of 100 kHz to 100 GHz and the Saser 0.1 to 1 THz. This connects directly to the Saser above the maser.

In A. J. Kent et al. published in 2006, work function semiconductor layers as the active medium. These layers consist of alternating AlAs and GaAs, and the incident sound wave excites the electrons therein. The so- induced lattice vibrations, called phonons, are ultimately responsible for the amplification of the sound wave. Under suitable conditions, these phonons oscillate in phase with the incident sound wave and lead to an increase in amplitude. Since the oscillation frequency of these phonons is not arbitrary, but depends on the material, only certain frequencies are amplified. Therefore, the output acoustic wave is not only amplified but also coherent.

Previously separating the phonon frequencies but do not succeed in clean, so that the output acoustic wave is a mixture of different frequencies. With a market is not expected in the near future.