Talk:Sound amplification by stimulated emission of radiation

I am a student working on the improvement of this page. I would appreciate any suggestions regarding the content of this very interesting subject. Any comments or ideas from people working on this are very welcome. I am sure that any interaction would be extremely helpful and productive here. Through my work to improve this article - which is listed as a “stub-class” at the moment – I have added two images trying to explain superlattice and stimulated emission of phonons and another one photograph showing a particular procedure of making a sound laser. I have also added “Design” and “Proposed Schemes” sections which are probably going to be followed by an “Experiments” or "Proposed Devices" section. In addition, I am currently improving the introduction section. My next step here is to describe the two basic studies of phonon laser from Nottingham and Caltech groups. I will then focus on the “Physics” section. My aim is the article to be reader-friendly and as complete as it could be for now. Philipposc (talk) 12:03, 08 February 2013 (UTC)

Phonon energy
If I understand correctly one phonon can excite multiple electrons as it says 'one phonon going in, produces two phonons coming out'. Are the phonon's produced the same energy as the original phonon or are they at different energy's as the electrons are on different levels of the lattice? Does the phonon in the lattice lose energy when exciting an electron? Does it have energy left to excite other electrons? ACGrain (talk) 16:55, 22 February 2013 (UTC)

edit - from now reading the two layered system I am confused, the electrons are all ready excited and the phonon is just causing them to decay and emit another phonon? So the two phonon's from the first phonon are the original phonon plus a new emitted one from an already excited electron? Is this just for a two layered system? As I find this is conflicting with the physics already discussed. ACGrain (talk) 17:19, 22 February 2013 (UTC)

Well that is a good notice. I think there is an unclear meaning about the phonon energies and I am planning to "fix" it. Thank you for pointing that! Any kind of improvements on this subject are very helpful.

In general, as it is well known, external energy pumping (e.g a light beam or voltage) can help to the excitation of an electron. This briefly leads to vibration of the lattice and thus to phonon generation. The vibration energy of the lattice can take discrete values for every excitation. Every one of this "excitation packages" is called phonon. An electron does not stay in an excited state for too long. It readily releases energy to return back to its stable low energy state. The electrons release energy in any random direction and at any time (after their excitation). At some particular times, some electrons get excited while others lose energy in a way that the average energy of system is the lowest possible. Now, by pumping energy into the system we can achieve a population inversion. This means that there are more excited electrons than electrons in the lowest energy state in the system. As electron releases energy (e.g phonon) it "communicates" with another excited electron to release its energy too. Therefore we have a stimulated emission which means a lot of energy (e.g acoustic radiation, phonons)is released at the same time. ...So, we can imagine the stimulated emission like a procedure where we have a spontaneous and an induced emission at the same specific time. The induced emission comes from the pumping procedure and then be "added" to the spontaneous emission.

Notable fact: Due to connections between atoms, the displacement of one or more atoms from their equilibrium positions, will give rise to a set of vibration waves propagating through the lattice. This is, in a way, how sound propagates in a lattice (or superlattice).

Philipposc (talk) 21:25, 25 February 2013 (UTC)

Diagrams
Here's a useful link where you can request image improvements http://en.wikipedia.org/wiki/Wikipedia:Graphics_Lab

Might be useful for the wave function on http://en.wikipedia.org/wiki/File:The_structure_of_a_superlattice_of_semiconductor_AlAs_and_GaAs_layers._Acoustic_waves_undergo_amplification.jpg

ACGrain (talk) 11:24, 4 March 2013 (UTC)

comment
I personally find the article very interesting and well explained. The provided information covers the history and physics of SASERs very thoroughly. The charts and diagrams used contribute greatly to the nice flow of information. The part explaining proposed schemes and examples of SASER devices contributes to an understanding of the practical aspect of sound amplification. I would be very interested in finding out more about the use of SASER in chip technology, learning about the experimental phase of phonon incorporation in computer science.

Nikaramic (User talk:Nikaramic) 23:02, 22 March 2013 (UTC) — Preceding unsigned comment added by 93.97.131.143 (talk)

Page Name?
Shouldn't this page be called 'Saser'? The 'laser' page is called 'laser' not 'Light amplification by stimulated emission of radiation'. Also I don't think the word 'saser' should be in all caps throughout the article. How do I change the page title names?2.121.73.179 (talk) 21:40, 22 May 2013 (UTC)

I don't think that it should be called SASER because the word is not well known yet. For example it is currently different from the word "LASER" as when you say "LASER" today we all know the meaning. This is not happening with the word "SASER" though! If you really have a reason just click on "edit" and change the title! Philipposc (talk) 14:40, 23 May 2013 (UTC)

External links modified
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citation found?
There is a place where it says citation needed. Maybe this is the proof of SASER technology working in 2009... https://www.nottingham.ac.uk/news/pressreleases/2009/june/sonicboom.aspx. — Preceding unsigned comment added by Prepper64 (talk • contribs) 10:44, 13 February 2018 (UTC)