Talk:Laser/Archive 3

Lasers are masers
Hello. So I believe there is a problem with this article. Namely, the discussion of what a maser is has become anachronistic, and misleading, and thus the way it is presented in this article is, well ... wrong. The issue is a bit tangled. So, as is stated, lasers were first derived from the developement and conceptual framework of the maser, where a maser was essentially the same type of device but restricted to the microwave region of the spectrum. However, this is an old definition it seems. It doesn't require much research to confirm this claim. There are now a large number of "masers" that have been developed which operate all around the rf spectrum, even near the bottom of the VLF. These are very clearly not "mircrowave devices." This is because a maser is generally meant to stand for molecular amplification by stimulated emission of rediation.

Now, this is extremely important for a number of reasons. The first being far too many "experts" who work with lasers are completely ignorant of the fact that these types of devices exist for a large array of spectral frequencies, and that each has very unique, interesting, and important features (I can give details if you like). In fact stimulated emission can and has been extended to fairly exotic settign. Second, if one wants to extend the defintion of a laser to include these devices, then one needs to explain that when one refers to "light" one is really thinking of "light" as a any type of photon emission; which is not usually the case, and thus a bit of a non sequitur. Third, though this article is quite nice in some ways, and provides a decent background in an engineering sense, its theoretical part is quite absent. Though it s true that laser is a device, it is also true that a dishrag is a device. The word device carries no inherent laser-ness. It is a wasted noun. On the other hand, a laser is a maser, which is also a device, and is a word that carries details related to the actual underlying properties of system, plus leading, in an expansive way, to the more theortic issues at hand. When I say recent advances in maser research, the word recent is used euphamistically. In fact, masers have been around in this permuation of there meaning for at least a decade. Anyway, parts of this page need to be rewritten in order to get this up to date with the current science. 66.143.168.143 20:47, 16 July 2005 (UTC)


 * You've still cited no source which corroborates the (nonsense) claim that "a laser is a maser". MASERS work in the GHz spectrum and below and lasers operate in the UV, visible and IR spectrums. That's it. The fact that stimulated emission has been extended to exotic regimes in no way validates the claim that lasers are some kind of subset of masers. There are X-ray lasers now in existance as well, would you claim that lasers are actually a subset of masers? No one conventionally defines them that way . If, as it seems you do, fancy yourself such an expert above the experts you'll have to provide a much better argument than you have here for the changes you want to make to the fundamentally accepted definition of a laser. I might also remind you that wikipedia is also not a place for original research or the changing of widely accepted definitions to suit an editors whim or suspicion. --Deglr6328 21:01, 16 July 2005 (UTC)


 * Frankly I'm shocked. Anyway, I appreciate your concern for rewriting conventional definitions.  Luckily, that is not what I am proposing, but rather to get the current one into the 20th century :) (maybe the late 20th century ;-)).  So, the term maser, as refered above and on the link, was given by the Nobel prize winning physicisat at least as early as 1964 (please see the links at the maser article).  That being the case, then the answer to your confusing question is mostly yes.  A xaser is a maser, a laser is a maser, a raser is a maser, and a maser is a maser.  If you wish, an optical laser is a maser, an x-ray laser is a maser, a radio-laser is a maser, and a microwave laser is a maser.  This is confusing though, since light almost always conventionally refers to the optical spectrum.  So, there's that.  A xaser is not a laser though, since they operate at totally different frequencies.


 * Now, the link to the photonics dictionary is not at issue. That definition is accurate up to the level at which it defines itself (in other words, it does not pressume to subsume the definition of a maser or an x-ray laser in that article.  I am refering to the article here at wikipedia.


 * Now, since atoms are molecules, our confusion ablates once we start looking at the way in which stimulated emission actually works in these systems. The Zeeman exchange maser is a good example of a maser which does not have to operate in the microwave frequency range at all.  For background and info, see:


 * 1. T.E. Chupp, R.J.Hoare, R.L. Walsworth, and Bo Wu, Spin-Exchange-Pumped He and Xe Zeeman Masers, Physical Review Letters, 72 (1994) 2363-2366


 * 2. C.V Rice, and D. Raftery, Rubidium–xenon spin exchange and relaxation rates measured at high pressure and high magnetic field, Journal of Chemical Physics, 117 (2002) 5632-5641


 * 3. M.G. Richards, B.P. Cowan, M.F. Secca, and K. Machin, The He nuclear Zeeman maser, Journal of Physics B: Atomic, Molecular, and Optical Physics, 21 (1988) 665-681


 * There are hundreds more (actually thousands). You might save me the time by going to web-of-science and doing a couple searches on your own.  It is true that some people say x-ray laser, some say xaser, and some say, more generally maser.  That is why we so desperately need to clarify the terminology, so people can read the literature without being more confused.  66.143.168.143 22:02, 16 July 2005 (UTC)


 * Btw Deglr6328, the term raser is used in the literature (and could use a wikipedia entry btw) - in reference to your comment on the maser page. It does not get alot of use in titles, but occasionally it does, and it has made it into the body of many texts on related topics:


 * 1. Bosiger, P.; Brun, E.; Meier, D., Instabilities and phase changes of the first order of the ruby raser, Helvetica Physica Acta, vol.52, no.3, 25 Jan. 1980. p. 375


 * 2. Yu. M. Seidov, É. M. Shakhverdiev, and I. I. Abbasov, Condition for generation of radiation in rasers, TECHNICAL PHYSICS 42 (10): 1238-1238 OCT 1997
 * 66.143.168.143 23:11, 16 July 2005 (UTC)


 * No, and now I strongly suspect that you are trying to insert nonsense into the article merely to see if you can. With GROSSLY scientifically inaccurate statements like "Now, since atoms are molecules..." and "A xaser is a maser, a laser is a maser, a raser is a maser, and a maser is a maser." then later "A xaser is not a laser though, since they operate at totally different frequencies.", I just don't know what to say. I mean what do you think "xasers" and masers operate at? The same frequency? Virtually no one uses "xaser" and no one EVER uses maser to describe x-ray lasers. Your statements are rife with incomprehensible gibberish and frankly I don't know what your citations are supposed to prove at all. Zeeman masers are zeeman masers. That's it. So what. Also the sentence that you keep inserting in the maser article:


 * "maser...acronym has been appended in the current usage, and is usually taken to stand for "molecular amplification by stimulated emission of radiation" [1]. Under this defintion, an optical laser is a specific type of the more general maser"


 * is just wrong. This usage gets ~20 hits on google (most of which are merely repeats of a what seems to be a widely distributed, originally french, acronym list and the rest seem to be mostly mentioned on openly posted physics forums or science fiction novels) it gets precisely NO hits on a scitation search. I doubt anything of much value can be gained from continuing this conversation. Please stop adding nonsense to wikipedia. It is not the job of wikipedia to redefine terms. It is insanely frustrating to have to constantly spend time arguing with anonymous editors who insist on inserting incorrect information on wiki.  --Deglr6328 23:38, 16 July 2005 (UTC)

Deglr6328, have you lost your mind :). Yes indeed, what is a Zeeman maser.  Can we please be civil btw, I am no newbie to wiki or to science, and it is unlikely you can disuade me with your blatherskism.

So first, yes, an atom is a molecule by the definiton given, of all places, here. Though often we talk of bound states here in my chemistry and physics departments, the issue right now is one of conistency with definitions (that is, the defintion of the maser in particular). Geez, must I explain such an elementary concept? So we have molecular gases, then we have monatomic gases, etc ... so which would a noble gas be? (common usage, wikipedia definition, etc.). Look into it, you might be surprised (google could work as well). Let me provide a bit more explanation for the uninformed. In statistical kinetics (generally physical chemistry that is), for example, we often deal with ensembles of atoms, wherein we deal with things called molecular collisions. This is pretty basic, and you may argue confusing, that kineticists use the term molecule to refer to atoms in atomic gases. Nonetheless, nobody apparently asked for your permission, since that's the way it's been done for decades now. So that's cleared up.

Now let me explain what a maser is one more time. A maser is any amplifier that produces coherent electromagnetic waves due to stimulated emission. In current usage it stands for molecular amplification by stimulated emission of radiation. Notice the word molecular.  Is it coming together now? The reason I reference the Zeeman maser is because, for example, in the reference above, if you considered actually reading it, you would have noticed that one of the coupled Zeeman masers operates at 3510 Hz (can you guess which one? -- you could always read it). Is that in the microwave range? If you answered no then we're getting somewhere. As far as xasers are concerned, you're not wrong. It seems to be standard in the x-ray laser community to refer to x-ray lasers as x-ray lasers. Which is fine. Does that mean that an x-ray laser is not an amplifier that produces coherent electromagnetic waves due to stimulated emission? -- no. So what is your point? If your point is you haven' ever used this term, then, as shown with raser and molecule, the answers has to be, so what?

And what do mean by 20 hits? What is that based on? What are your search terms and what is your search engine? I can give you mine if you like.

Anyway, If someone else would like to step in I would be much obliged. I have read many articles on these subjects, and all that I am interested in doing is clarifying the language, not getting into a 10 year olds flame war. If you need more references, I guess I can provide them. If you would like me to explain any of the mathematics or physics in any of the references I've already given, I suppose I can teach you that (though if I have to, then why are you arguing with me?). If you need other examples of masers that are not microwave, I can do that. What I can't do is sit here while you present no facts, provide no citations, and demonstrate no coherent argument at all as to why I am wrong (other than pointing out your confusion on varying related levels of science); and doing so in a rude and obnoxious way. I mean, how many times must you be wrong before you take on a more humble attitude? You were wrong when you said rasers are in theGHz range, your were wrong when you said "term raser is nonexistant in the literature," your were wrong when you said and atom is not a molecule, and you were demonstrating you inability to reason when you said "Your statements are rife with incomprehensible gibberish and frankly I don't know what your citations are supposed to prove at all;" as that would have been clear had you spent any time reading them at all. So, in the name of this discussion, why don't we just accept that maybe you know some things, and maybe I know some things, and together we might be able to straighten this out. Deal? 66.143.168.143 00:43, 17 July 2005 (UTC)


 * If you are trying to claim that because the term maser can be applied to VHF emitting devices (zeeman masers) then the term can also be likewise applied to lasers and "xasers" you are wrong. The term is not conventionally used this way. While the term "raser" might not be nonexistant and I was technically wrong there, it IS *virtually* nonexistant in the literature (do a scitation search, there is precisely ONE relevant paper ever published with the term). And I never said Rasers are in the GHz range. I said Masers are considered to be in the GHz and below region. Furthermore, to say that "individual atoms are also called molecules" is to stretch and confuse a definition so incredibly thinly as to be laughable. You seem to be bent on using the most arcane and torturous definitions of terms possible to suit your needs. Ironic since you claim to merely want to 'make things clearer for the reader'. Your citations of Zeeman masers no more proves that lasers are masers than it proves xasers are masers. This is really absurd. Anyway, whatever, like I said I'm done here, there is enough conversation above to allow other editors to see the situation make any appropriate future edits. --Deglr6328 01:13, 17 July 2005 (UTC)


 * Okay. Bye then.


 * Let me add a couple parting words to any spectators who are present. The first, for those of you who don't know, Scitation articles really only go back to ~1996.  This being the case, what Deglr6328 said is true, there is only one citation for raser in this search engine.  However, if one uses, for example, web of science, one gets about 10 more.  Now, this still seems like not very many, and it isn't.  However, this only represents titles and abstracts with raser in it, not full scale texts which may mention rasers.  This is why the term, which is fairly well-established as an alternative termoinology, is not used very often.  It is certainly fair to say it is rarely used, or even that it is resisted by the scientific community for whatever reason.  As a matter of fact, I would recommend against using it unless you really know what you're doing.


 * With regards to the defintion of a molecule, I must admit to having been a bit confused myself at first by this. When I first saw the acronym for maser expanded as "molecular" I thought of covalently bonded (or bound state) phenomena, and thought the defintion was that much more confusing.  But as I thought it over, and dug a bit deeper, I found that using the kinetic definition is actually extremely natural.  For example, in a spin-exchange maser, the spins are exchanged due to atomic collisions, which leads to the coherent state of the system.  Thus, in the terminology of collisional kinetics, a molecule is just the base element.  I do however agree that this can be confusing initially.  I hope that makes it clearer.


 * Finally, the basic confusion has been obfuscated I think by alot of nonsense, so let me restate it as clearly as I can. The word maser is most often taken to be an acronym for "microwave"-aser.  However, it is basically standard to refer to what may be termed rasers as also being masers.  That is stimulated emission in the radio frequency range of the spectrum.  Thus, one of two things must be true.  One, that the traditional acronym for maser is false, in that a maser is not a microwave-aser.  Or two, the acronym is correct and rasers are not masers.  If one looks at the literature, they will quickly see that the second option must be patently false, as there is simply too much literature on masers that emit in the radio frequency range, such as the ones mentions above in the references.  Thus, one must consider that the acronym "microwave-aser" is somehow wrong or misleading.  Along these lines, many have been led to a similar conclusion.  Most notably, Charles H. Townes, the noble prize winning physicist in maser and laser research, presented no later than 1964 the appended acronym for maser that is "molecular amplification by stimulated emission of radiation."  A quote from Townes in 1964, that is referenced here , goes "The idea [of stimulated emission] has been successfully extended to such a variety of devices and frequencies that it is probably well to generalize the name - perhaps to mean molecular amplification by stimulated emission of radiation."


 * Now, the problem is, as is always the problem, this ruffles feathers in people who prefer the incompressible contradiction that they are used to, rather than a scientifically rigorous definition that makes some sense. So, if we define maser as "microwave-aser," then many of the masers in existence today are, by definition, not masers.  However, if we use Townes' generalization, then these modern masers are masers, but unfortunately, then lasers, xasers, etc. are also masers, as the definitions subsumes those at this point by thinking of molecular-aser in the kinetic sense.  This is very frustrating to people apparently.  The point is, this mess is not "my" mess, this is a mess generated by alot of other people, but must be made sense of.  Whatever is ultimately most preferable to the wikipedia community is fine with me; but many, not just me, and not just Deglr6328, have been confused by this, and so it must be mentioned when one is going to mention masers at all in an article.   And insults and threats of illegitimacy are irrelevent, this is the state of things which I think can be confirmed when one looks into it a bit.  What we need is an explanation, because though a defintion on wikipedia is not meant to "change" or redefine scientific terminology, it is meant to reflect the state of the field in question.  And so, since the state of the field is confusion, we have the option of either presenting that confusion in the state it exists in in its entirety, or provide some direction by which people can find their way therough the labyrinth on their own and arrive at the correct conclusions.  What is currently presented in this article does neither. If nobody feels qualified to make the necessary changes, or iof they are having truble understanding the nature of the issue, then I can do it easily.  However, in an attempt to observe the community spirit of wiki, I would like to ask if anybody has any other comments before I do so.  66.143.168.143 05:13, 17 July 2005 (UTC)


 * "Most notably, Charles H. Townes, the noble prize winning physicist in maser and laser research, presented no later than 1964 the appended acronym for maser that is "molecular amplification by stimulated emission of radiation."
 * Who uses this term?! nearly nobody exept you! It gasped its last mere seconds after it was suggested by Townes just like graser and UVaser and countless other suggested scientific terms. If we want to avoid confusion for the reader, the first thing we should be doing is NOT basing our explanations here on dead/invented/unknown/unaccepted/totally disused definitions. Its pointless. That is all. bye.--Deglr6328 05:59, 17 July 2005 (UTC)

Geez Deglr6328, why such desperation? The world will go on. Consider this. The terminology of the laser could be equally confusing, as light 'usually' refers to the visible spectrum. However, with the popularity of the term laser, the term light in the acronym has been extended to mean really any energy of photon. So an xray laser, an ir laser, a uv laser, etc., all operate with photons, so we can make sense of the terminology, and think of them all as lasers. However, with a maser we have "microwave" to deal with. It seems impossible to extend the meaning of microwave to radio frequency, etc. One perhaps could have wished that maser hadn't caught on, and that people refered to microwave-asers as microwave lasers, and rasers as rf-lasers, and thus the issue would never have been important. But, unfortunately this has not been the case. Instead, stupid people like me, spend several days of their lives trying to understand how in the world a maser could emit in the VLF. Since the answer is staring us in the face, namely the appended acronym above, the only reasonable conclusion is that everyone who uses maser to refer to rf-lasers is implicitly taking as an acronym "molecular-aser;" as otherwise they would be making inconsistent statements. In fact, this seems to be the case when you talk to these people. Maser seems to be the more general term. But even if it weren't, don't you think it is the role of places like wikipedia to clarify these types of issues for the general public, as really this is just a semantic issue having to due with common usage of basic terminology? Perhaps there is a way of presenting this that would be less upsetting to you? 66.143.168.143 06:56, 17 July 2005 (UTC)

Hi, just to clarify something, I'm an optics student and we have always been taught that Maser refers to the original official definition, "molecular amplification by stimulated emission of radiation". I hadn't come across maser referring to microwave wavelength lasers before, and possibly this is the same for all students new to the subject, and so is possibly a definition not used at all anymore?


 * As a counter-example, as a Ph.D. student in optoelectronics a few years ago, I never heard of the term "maser" meaning anything but "microwave amplification by stimulated emission of radiation". Looking into it further (e.g. from the discussion here, and from Jeff Hecht's book Beam), it looks like the term "optical maser" is/was mostly used by those who wish to emphasize Schawlow and Townes' and Bell Labs' (substantial and very important) contributions to the field. Notable among those who have chosen to emphasize these contributions are Bell Labs and Townes himself. I have tried to more or less obliquely refer to this situation in the text, and I included a link to Bell Labs' web page describing the history of the laser, written in 1998, showing that by that time even Bell Labs had begun using the term "laser". As for what is the correct expansion of the acronym "maser", that is a question for the Maser article, not the laser article.
 * PS It is helpful to sign your contributions to Talk pages using " ~ " if you have an account, or otherwise by some name you want the rest of us to think of you as.
 * -- The Photon 01:05, 5 December 2005 (UTC)


 * I second the opinion of The Photon. --danh 18:00, 5 December 2005 (UTC)

Has anyone made a LASER weapon
If you have made one please tell me how you made it(I already know how to make one). Dudtz 8/19/05 6:51 PM EST

Image:Laser spectral lines.png
http://en.wikipedia.org/wiki/Image:Laser_spectral_lines.png

I found this picture misleading:
 * no uniformity in the font usage: Nd:YAG vs HO:YAG (is it holmium and oxygen doped YAG? )
 * RAMAN lines vs Ramen shifted
 * El:YAG >>> should be Er:YAG
 * Nd:YAG/Glass and Nd:YAG & Nd:Glass

Where is the He-Ne laser lines? (at least ~633 nm) Where is the UV representitives (excimer lasers)?


 * Can you fix it or make a new one?--Deglr6328 04:06, 26 August 2005 (UTC)

I need a video
Can anyone give me an url where I can get a video about how works a cd-reader (the pick up part)? I need it for a school work about lasers

Darío Lescano - dariofl@latinmail.com

Gordon or Gould coined terms and gained patents?
In the history section, the article states Gordon also coined the word iraser, intending "aser" as the suffix and the spectra of light emitted at as the prefix (examples: X-ray laser = xaser, UltraViolet laser = uvaser) but these terms never became popular. Gordon was also credited with lucrative patent rights for a gas-discharge laser in 1987, following a protracted 30 year legal battle. It is not clear whether "Gordon" refers to Townes' collaborator J.P. Gordon, or to the coiner of the term laser, Gordon Gould. According to recent obituaries, Gould was the one who received critical patents for the laser. The Photon 06:24, 30 September 2005 (UTC)

Formatting of the page
after recent edits, is now quite horrid in IE..... --Deglr6328 07:24, 5 October 2005 (UTC)


 * Apologies. I am not editting with IE. I'll do what I can to avoid images stacking up, and check it out in IE from work tomorrow.The Photon 03:58, 6 October 2005 (UTC)


 * Looks good now.--Deglr6328 05:18, 13 October 2005 (UTC)

History events that might be included
These are some historical developments that greatly overshadow the "recent innovations" included in the article, but I don't know enough about them to write them in to the article. I see several items creeping in that might be better off in Laser applications, but at least one or two of them are probably appropriate here as well. Please add to the list. The Photon 15:54, 11 October 2005 (UTC)
 * 1) Invention of C02 laser.
 * 2) Invention of optical fiber laser (gain medium doped into glass)
 * 3) Introduction of first commercially available laser.
 * 4) Invention of dye laser.
 * 5) Invention of the hologram (first gee-whiz use of lasers for the general public).
 * 6) Introduction of first successfully commercialized industrial laser.
 * 7) Introduction of first lasers visible to general population: supermarket scanner?
 * 8) Introduction of first consumer device with laser: laserdisk?
 * 9) Introduction of first mass-market consumer device with lasers: CD player.


 * CO2 laser in 1964, dye laser in 1966, Nd:fibre laser in 1961, EDFA in 1987. Holography was actually invented before the laser, in 1948. Not sure about commercial availability, etc. -- Bob Mellish 16:28, 11 October 2005 (UTC)

Rival Claimants to the Invention of the Laser other than Townes, Gould, Maiman
A somewhat speculative paper by Myers and Dixon cites the following two fellows as rival principal inventors of the laser. Nicolaas Bloembergen (three-level MASER) with U.S. Patent No. 2,909,654 (filed October 15, 1956); Robert Dicke with U.S. Patent No. 2,851,652 (filed May 21, 1956). From a IEEE paper (pub. date unknown, cited by Karl Jorda in Commentary, "The Thirty-Year Laser Patent War", IDEA, Vol. 43, No. 3, p. 545) "Who Invented the Laser?" by Robert A. Myers and Richard W. Dixon. Bloembergen is a Nobel laureate, and according to anecdotal evidence apparently erroneously did not think his invention applied to optical radiation (but presumeably, according to the paper authors, it does).

To cite natural forces as an "invention", the atmosphere of Mars essentially amplifies sunlight and acts as a sort of natural laser. This was brought up as a defense during the Gould litigation to try and defeat one of Gordon Gould's patents.

Definition again
"(A laser is) an optical source that emits photons in a narrow, polarized, coherent beam of near-monochromatic light, consisting of a single wavelength or hue."


 * 1) Therefore, most semiconductor lasers aren't lasers, because they don't emit particularly narrow beams. (Nor always lase in a single polarization The Photon)
 * 2) Therefore, many Nd:YAG lasers aren't lasers because they're often unpolarized.
 * 3) Therefore, a modelocked Ti:sapphire laser isn't a laser because it's far from monochromatic.

Recent edits are narrowing the definition of laser down too much, again. Please be careful about being to specific when it comes to the definition. --Bob Mellish 01:39, 13 October 2005 (UTC)


 * Why not fix it then?--Deglr6328 05:20, 13 October 2005 (UTC)

Proposal: "A laser is an optical source that produces light from an oscillating optical cavity, using stimulated emission as the gain mechanism. The output is highly coherent in comparison with classical artificial sources, and in many cases can be designed to be polarized and/or near-monochromatic. These features make lasers important because ... [gotta work on this part]" --- I would prefer to make the first sentence less technical---any ideas? Do we need to say "light or other electromagnetic radiation" to include x-ray lasers, etc? --The Photon 16:15, 13 October 2005 (UTC)


 * No need for the "These features make lasers important because" section as this is already present in the "uses" section.--Deglr6328 16:40, 13 October 2005 (UTC)


 * I'm more thinking of the "encyclopedic" style. (My opinion only) the first paragraph "ought" to summarize the importance of the whole article in as few sentences as possible. The whole article "ought" to explain to general readers (not physicists) why lasers are important to them. Some more subtle phrasing would be better than "X is important because".--The Photon 01:32, 18 October 2005 (UTC)