User talk:Srleffler

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Hi, feel free to leave me a message. Kindly leave messages on new topics at the bottom of this page. Srleffler

antireflective coating[edit]

(→‎Index-matching: "Normalized" is unclear here.)

The form is r=(n1-n2)/(n1+n2), squared for intensity. It is not proportional to n1-n2, but is close for small (n1-n2). I am not against your change, though. Gah4 (talk) 06:42, 9 January 2016 (UTC)

I know. Calling that "normalized" without further explanation isn't clear enough to the reader. Better to point them to Fresnel equations and leave it at that.--Srleffler (talk) 07:18, 9 January 2016 (UTC)


Hi, I removed the comment because it was one of several random utterings from that user going back weeks. See their deleted contributions for the worst examples. --Redrose64 (talk) 10:52, 9 January 2016 (UTC)

I understand. I assumed good faith on this particular edit.--Srleffler (talk) 14:00, 9 January 2016 (UTC)

Info deleted from Incandescent light bulb[edit]

In 2016, researchers have developed a way to improve the efficiency of the incandescent light. Incandescents right now only convert only 2-3% of their energy into light. The scientists created an incandescent bulb that converts 6.6% of the energy into light. They theoretically can convert 40% of the energy into light which is three time more efficient than LEDs. They have built a structure that surrounds the filament of the bulb and captures the leaking infrared radiation, reflecting it back to the filament where it is re-absorbed and then re-emitted as visible light.<ref>New development could lead to more effective lightbulbs, BBC News, 12 January 2026, Matt McGrath</ref>

This paragraph below is missing important info from the paragraph above.

Prompted by legislation in various countries mandating increased bulb efficiency, new "hybrid" incandescent bulbs have been introduced by Philips. The "Halogena Energy Saver" incandescents can produce about 23 lm/W; about 30 percent more efficient than traditional incandescents, by using a reflective capsule to reflect formerly wasted infrared radiation back to the filament from which it can be re-emitted as visible light.<ref>Broydo Vestel, Leora (6 July 2009). "Incandescent Bulbs Return to the Cutting Edge". The New York Times. Retrieved 6 July 2009. </ref> More advanced reflectors can theoretically be much more efficient. Laboratory proof-of-concept experiments have produced as much as 45 lm/W, approaching the efficacy of compact fluorescent bulbs.<ref>New development could lead to more effective lightbulbs, BBC News, 12 January 2026, Matt McGrath</ref><ref>Ilic, Ognjen (2016). "Tailoring high-temperature radiation and the resurrection of the incandescent source". Nature Nanotechnology. doi:10.1038/nnano.2015.309. </ref>

Would you consider adding some of the info from the first paragraph?

--Wyn.junior (talk) 23:31, 13 January 2016 (UTC)

The original paragraph put too much weight on this research result. It's a laboratory proof-of-concept experiment, not a developed commercial product. The 40% number is completely theoretical; it's not clear that even the researchers think they can approach that in practice. I think my version captures all of the useful information and puts it into proper context and with proper weight. What do you think is missing?--Srleffler (talk) 06:59, 14 January 2016 (UTC)

is a Keplerian telescope afocal?[edit]

Perhaps the author was thinking about a Keplerian telescope, but I do not think such a telescope matches the description given, while I think a Gallilean telescope does. While Kepler's design makes a generally better instrument, I think simple, "opera glass" telescopes are still quite common. --AJim (talk) 04:07, 25 February 2016 (UTC)

Answering my own question, yes, it is, under the specific conditions they specify. In fact they go on to show how the sign of the magnification tells whether the image is upright or inverted. I still think it could be helpful to a learner to make the connection from this theory to the two historical telescope names. --AJim (talk) 01:11, 26 February 2016 (UTC)

I agree. I added a link to the end of the section that points directly to Refracting telescope § Refracting telescope designs, so that readers who are interested in learning more about telescopes can. I think this is better than having an easter egg link to optical telescope. --Srleffler (talk) 02:11, 26 February 2016 (UTC)

Could I now put on Wikipedia.en references to my simulation program?[edit]

In April 2014, I made an attempt to put on Wikipedia.en my simulations, which are meant to help lecturing students in classical physics. You refused them, (see item 6 of the Contents list of your talk page) because you felt these simulations were not safe, coming from a personal google site. You wanted me to use a "certified" site, the one of an university for instance. Since that time, among others things, I moved my programs to the site of my former lab (I am now retired): the "Laboratoire de l'Accélérateur Linéaire" (LAL) at Orsay, which is one of the mean French lab in High Energy physics. So there should be no more safety problems. You told me also that the way my programs were proposed, as executable .jar's (java exec's), which are to be downloaded, were not very appropriate. So I stick to these .jars, which seem to me the most handy way to work. I ask you if it were any way possible to put my simulations on the english version of wikipedia. These simulations can be seen using the link:, with french items, all of them translated into English as well (the wikipedia.en visitors would go directly to english versions).

Best regards. Truocled (talk) 17:24, 4 March 2016 (UTC)Truocled

I won't stand in the way.--Srleffler (talk) 02:27, 6 March 2016 (UTC)
I apologize, but your answer is not clear to me (my understanding of English is still not perfect). Does it mean that you are not opposed to see my programms on Wikipedia.en, or that you are opposed to it? Truocled (talk) 14:33, 6 March 2016 (UTC)
It means that I won't prevent you from adding the links. (Not standing in someone's way means not blocking their path, stopping them from going where they want to go.)--Srleffler (talk) 20:16, 6 March 2016 (UTC)
I have put four external links on the pages; of Michelson and Fabry-Pérot interferometers, of Young slits and of microscope. Best regards . Truocled (talk) 17:54, 2 July 2016 (UTC)Truocled

Spectral Irradiance edit undo[edit]

It was that very difference I was trying to make clear, as if you didn't read my reason for the edit... maybe some extra commas would more properly relate correctly the clauses... ok went back to look at it again and now it is much clearer as to what is referring which. Better than what I did. DPHutchins (talk) 06:26, 7 March 2016 (UTC)

Your edit summary seemed to indicate that you didn't understand that the two types of spectral irradiance have different dimensions. Your edit was nonsense: "watt per square metre per the wavelength of a particular frequency in hertz" doesn't mean anything, and "W·m−2·λ−1" is just flat out wrong. "λ" is not a unit symbol.--Srleffler (talk) 06:58, 7 March 2016 (UTC)

Luneburg lens edit undo[edit]

Hi, could you please comment on your motivation about removing external link, because it is in a different language?

I agree that links to English language pages are more appropriate *if they exist*, but I've found only very short summaries in English, unlike the rather detailed instructions and description of the antenna "construction" and testing in my link. rado (talk) 08:42, 31 March 2016 (UTC)

The guidelines on this are at WP:NONENGEL. The English language Wikipedia is for people who read English. External resources in other languages are of no use to our readers, in general. Your link belongs in the Portugese Wikipedia.--Srleffler (talk) 00:50, 1 April 2016 (UTC)

Thin-film interference[edit]

Thanks for your assistance. That does look a lot better and more concise than what I had for the lede. I knew I should've just let you take care of it.

Part of my trepidation, however, comes from defining a term with that term. In example from our own article (which I plan to clarify soon): "A solid solution is a solid-state solution of one or more solutes in a solvent." (Huh?) Of course, I know what it's saying, but to the layman it's pure gibberish. Or until recently we had "Air combat manoeuvering (ACM) is the art of manoeuvring a combat aircraft." (Well, duh?) I know we have wikilinks to articles that (hopefully) define the terminology, but for the opening sentence I have usually found it helpful to clearly define the jargon for the layperson, so they don't have to click three different links to get the gist of it. Do you think there is a simple way to define both "thin film" and "interference" in the opening sentence, so that the definition doesn't seem so circular? Zaereth (talk) 00:16, 6 April 2016 (UTC)

I think it's fine as it is. It's not defining a term with the same term; it's breaking a term down into simpler concepts: thin-film interference is interference in a thin film. The linked articles are fine for the reader needing a thorough explanation, and the rest of the lede gives a good-enough overview for a reader who doesn't need so much detail. --Srleffler (talk) 03:39, 6 April 2016 (UTC)
Ok, sounds good. My first instinct was to simply look for some synonyms, but there really aren't any, so I thought I'd ask to see if you had any ideas. I guess in this case it's best to leave them as self-explanatory from context. Thanks again for your help. Zaereth (talk) 21:11, 6 April 2016 (UTC)


I've added a couple of ref at Numerophobia. Please check.--Vin09(talk) 05:59, 9 April 2016 (UTC)

I've deprodded the article. The reason is given in the old prod box on the talk page. Thanks! Uanfala (talk) 10:51, 9 April 2016 (UTC)


It appears Corrigendas Special:Contributions/Corrigendas has been changing refs links to on several pages that I checked. Including List of laser applications What's your view on this? Cheers Jim1138 (talk) 07:10, 12 May 2016 (UTC)

It's clear promotion of his own website. Corrigendas is clearly F.J. Duarte, from his past editing history. I don't have any doubt in his academic credentials or the merits of his work, but he has a long history of trying to promote it on Wikipedia --Srleffler (talk) 05:09, 13 May 2016 (UTC)
(also @Jim1138:) You both may be interested in this discussion which didn't get picked up at the time. I simply did not know what to do about it, nor do I know now. I was wondering something, maybe you guys can answer---just how notable is Duarte's work in that field? It's hard to judge as an outsider. --Nanite (talk) 07:26, 13 May 2016 (UTC)
@Nanite: Time for an ANI? Jim1138 (talk) 17:06, 13 May 2016 (UTC)
@Nanite: I don't doubt that Duarte is notable, but he seems to have been promoting his work, his websites, and his books on Wikipedia for a long time. There is clearly undue coverage of his work here, and many external promotional links that should be removed. He has a lot to contribute on his topics of interest, but seems not to be able to avoid conflict of interest.--Srleffler (talk) 03:18, 14 May 2016 (UTC)

I did a quick survey of articles that link to his article. Not all of what I found was objectionable; perhaps most would not be if it were posted by someone other than Duarte himself. I don't doubt that he is notable, and not all discussion of and references to him and his work are undue. The worst things I found were references to articles on the "Optics Journal" website, which appears to be a fake journal owned by Duarte himself. While its perfectly legitimate for him to self-publish essays and editorials that way, there is absolutely no way under WP:RS that those works should ever be cited on Wikipedia. Particularly egregious was self-published criticism of Kodak and several of its executives, which was discussed and referenced in several Wikipedia articles. I removed references to "Optics Journal" wherever I found them, but probably missed lots.--Srleffler (talk) 04:46, 14 May 2016 (UTC)

Yes, I noticed this myself from the dye laser article. Duarte is definitely notable, especially in the field of lasers and dye lasers in particular. However, there were some truly bizarre edits from multiple accounts (Corrigendas, Northryde, Singlephoton, CSCarlton, to name a few) as well as a slew of similar IP addresses. Weird edits, such as linking his name in every reference where it appeared. That provoked me to put Duarte's article on my watchlist. Lot's of edits to references. Many edits, however, were perfectly good and even helpful, so I wasn't sure what to make of it, but have been watching closely. I usually don't revert unless it's like blatant vandalism or something, so I was kinda waiting to see what others would make of it. Zaereth (talk) 07:24, 14 May 2016 (UTC)

Question about image[edit]

Hi Srleffler,

Helical fluorescent lamp spectrum by diffraction grating.JPG
Fluorescent lighting spectrum peaks labelled.svg

I had a question about a diagram. I'm not too familiar with copyright laws, especially with images, so I usually upload only my own, and typically only when I se a need for one. I was fooling around one day with this image of a fluorescent lamp in a diffraction grating, and decided to cut a strip from the center and paste it to the graph. Lo and behold, all the peaks matched up almost perfectly. I thought it looked really good, adding some color to the graph. I tried to contact the author of the graph, but they seem to have disappeared.

Do you think it would be ok to upload the modified image as a derivative work, attributing it to the author of the graph? I think it would add both some aesthetic value, plus help the reader visualize where the visible peaks are on the chart. A problem is that I am not able to do anything with SVG files, so I'd have to upload as a JPEG. Do you think it would even be worth it? Zaereth (talk) 22:02, 23 May 2016 (UTC)

Yes, it's fine. You can read the license yourself at the commons page. You're free to modify the image and reissue it under the same license as long as you list the other contributors. See the "author" box on that page for an example. The ability to modify contributions to the project is a key part of Wikipedia's structure. Go for it.--Srleffler (talk) 06:10, 24 May 2016 (UTC)


I see you reverted my recent edit here. You are welcome to claim that a 0-dioptre lens does not technically converge rays of light at infinity (though this is what is "mathematically" suggested when you divide 1 (the length of a meter) by zero (the dioptre of a zero-dioptre "lens")). That is semantics, and I won't argue it. That there is no such thing as a zero-dioptre "lens" is untrue, however, and I wish you would reconsider that part of your reversion: how do you describe the dioptre of a flat piece of glass? Does a piece of glass exist as a lens at a dioptre of +0.00001 but then cease to be one when it reaches +0.0? If so, that is also semantics and the lay reader will not grasp it. Stating that a flat sheet of glass has a dioptre of +0.0 is a very useful concept for the non-expert who is struggling with the concept of correction. Wikipedia is intended to be for non-experts. Saying that a 0-diopter lens is a flat piece of glass is not untrue— it is just not the usual way of describing such a thing, and that makes it a very useful thing for understanding the concept of dioptre! I invite you to reintroduce this idea into the article somehow, if you would. If you didn't like my phrasing, then I would very much like to see your own, yes? Thanks! KDS4444 (talk) 10:32, 5 June 2016 (UTC)

I added something to the article. See what you think.
A refractive element with no optical power is a window, not a lens. Whether an element with a power of 0.00001 D is a very weak lens or an imperfect window probably depends on its intended application. It's semantics, but semantics matters even when talking to non-experts. Talking about a nonsensical optical element that doesn't exist is not going to help a naive reader to understand better. A naive reader is not going to understand what a "0-dioptre lens" is, but they do know what a window is, so it's better to explain that windows have no optical power (0 D) than to talk about a nonsense 0-dioptre lens.--Srleffler (talk) 00:21, 6 June 2016 (UTC)