This is the
talk page for discussing improvements to the
Diffraction grating article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This
level-4 vital article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||
|
The jupiterscope is a wibbly vinyl diffraction grating that could be placed on a camera lens There are also candies with diffraction gratings pressed onto them to have vivild pure colors These are of note as the jupiterscope could make greasy glass also become a diffraction grating from the impression The candy reminds us that cheap nanoprinting on carbohydrates is possible
The dimension and period of the grooves must be on the order of the wavelength in question.
echelle gratings
A fundamental property of gratings is that the angle of deviation of all but one of the diffracted beams depends on the wavelength of the incident light.
Therefore, a grating separates an incident polychromatic beam into its constituent wavelength components, i.e., it is dispersive
When groove spacing...
Booo science club! Hooray understanding! Viva la understandionne!
Because it isn't correct. 'Dimension' is easy to understand. 'Period' and 'order' in the context of science are also straightforward, anyone with any interest whatsoever in diffraction gratings will understand these.
Agreed. I'll put up an article or expansion request.
It would take a few minutes of research for any half-intelligent person to get up to speed here. Again, if you're anything to do with science, you should know these.
Good grief, just do your homework. Nothing in this article is difficult to understand. Sojourner001 22:54, 18 January 2007 (UTC)
According to http://scienceworld.wolfram.com/physics/GratingEquation.html and some supplier's catalogs (www.thorlabs.com) the diffraction equation should be dsin(theta_incident)+dsin(theta_reflected)=m(lambda). There should be no minus sign. I'm not sure how to edit the equations, so I'll trust that someone else will do this. -- 128.196.213.163 21:59, 30 October 2006 (UTC)Anon
How are groove period and groove density related? Are they inverses of one another? The article leaves this unclear, but an inverse relation is implied when the units are compared... —The preceding unsigned comment was added by MyOwnLittlWorld ( talk • contribs) 16:39, 27 February 2007 (UTC).
I don't think an LCD can cause a diffraction pattern, and am pretty sure if it could it wouldn't look like that. Is the picture instead an example of Newton's rings, caused by the close but imperfect separation between the LCD surface and the protective plastic screen? Atropos235 19:12, 18 February 2007 (UTC)
Agreed. The color pattern in the photograph, is in no way reminiscent of the pattern created by a periodic structure (like the pixels of an lcd in this case.). Also the spacing of the pixels is too large to produce significant diffraction effects with visible light. I would guess what we are seeing has to do with the polarization of light, passing through the polarizer in the LCD screen. Transparent plastics have the property that they can rotate the polarization of light with a degree depending on how much stress is applied to the material; this effect is also wavelength dependent. This could cause different regions to reflect different colors of light. -- V. 03:36, 3 March 2007 (UTC)
Having seen similar patterns on the LCD of my own cellphone, I found that after cleaning its surface they disappeared. So, in my case, it does seem to be caused at least in part by a thin-film effect, produced by oil (from either my own body or something I handled) left on the surface by my fingers. I infer, partly from the wave-like images in the top part of the pictured LCD, that the thin-film and polarizer effects may both contribute to what we see. 71.163.224.207 ( talk) 19:25, 7 April 2016 (UTC) -- SlinkyManatee
LCD screen definitely can make a diffraction. See my posting at
Isaacto ( talk) 10:31, 31 January 2017 (UTC)
I also don't think the original photo is diffraction due to LCD. On the other hand, if LCD is not cited as an example I feel something is lost, since it is the diffraction grating that is available to about everybody, and can be easily measured and checked against the theory. 1.36.38.215 ( talk) 13:47, 2 February 2017 (UTC)
I've written a section, edit it like hell. I tried to put one of those photos as a demonstration, but couldn't get Wikipedia to be able to verify it as "suitable for Wikipedia Commons". Any hint is appreciated. 1.36.38.215 ( talk) 14:29, 3 February 2017 (UTC)
I've uploaded the photo. I think it is more to do with insufficient information I've given to the image that I can't upload it initially. Thanks for your help! And let me know if you have any comments. Isaacto ( talk) 04:46, 4 February 2017 (UTC)
What is the lines-per-inch of a CD or a DVD?- 69.87.204.209 21:02, 1 June 2007 (UTC)
Does anyone feel up to the challenge of writing something easier to understand? If I didn't already know what to expect I wouldn't understand it. RJFJR 17:16, 14 June 2007 (UTC)
It is my understanding that it isthe thin film effect that causes interference patterns in reflected light from the dataside of cd's and dvd's and that the example on teh page needs to be removed. Allywilson ( talk) 16:40, 18 November 2007 (UTC)
I have re-arranged this article, and added some new bits to make it, I hope, more comprehensible, and to have a more logical structure.
The section on 'gratings as dispersive elements' is still a bit of a mish-mash, and I will do more work on this. I don't know enough about the manufacture of gratings to do anything with this section, but I suspect it is very sketchy and imcomplete Epzcaw ( talk) 13:28, 26 May 2008 (UTC)
I believe that it is important to discuss the concept of diffraction efficiency either within this page or on a page of its own. I think it should be a section within this page. To those who don't know diffraction efficiency is what percent of the incident light is diffracted to a particular diffraction order in reflectance or transmitance (The efficiencies are generally different). Resonant gratings can be designed that for specific conditions (angle, wavelenth, polarization) the diffraction efficiency of a particular order will be 100%. Eranus ( talk) 07:44, 24 July 2008 (UTC)
This is a bit more for the physics students and not the classical way to view diffraction. Since gratings are periodic, one can use the formalism of solid state physics which deals with periodic structures on the atomic scale. Anyway a homegeneous surface can not change the momentum (propagation vector, k) parralel to the surface. This is the relation between translational symmetry and conservation of momentum. A periodic structure conserves only crystal mometnum also known as quasi momentum, it means that the momentum is conserved up to a reciprocal lattice vector K (1/peiod), so if the grating is periodic in the x direction and the structure is homogeneous in the y direction, then
where m is the diffraction order and n the refractive index in the region of diffraction (reflection or tansmition). The way form here to the grating formula is very short, all form symmetry point of view. Will be glad to hear opinions if this should be included (Of course better worded) Eranus ( talk) 07:44, 24 July 2008 (UTC)
I certainly think the description of diffraction gratings which uses QED should be included or some form of explanation using photons - it's quite important to realise that this can't just be explained using waves.
Anon. —Preceding unsigned comment added by 92.15.40.214 ( talk) 18:49, 7 August 2009 (UTC)
Hi, everyone. I'm new to this. To get the ball rolling on QED in this article, I've written up a little piece using Feynman's example in his book. However, I'm young, with much to learn in the wonderful field of quantum electrodymanics, in which I've just begun to swim—nearly all of my knowledge of it comes from Feynman's book. So please, edit the heck out of this, both in language and in content—it would be nice to see a quantum electrodynamical explanation of diffraction gratings here. Also, I'll scan the images from QED when I get the time.
QED (quantum electrodynamics) offers a derivation of the properties of a diffraction grating in terms of photons as particles. In short, QED models photons as following all paths from a source to a final point, each of which has a certain probability amplitude, which can be represented as a vector or complex number (equivalently), or as Richard Feynman simply calls them in his book on QED, "arrows". For the probability that a certain event will happen, one sums the probability amplitudes for all of the possible ways in which the event can occur, and then takes the square of the length of the result. The probability amplitude of a photon from a monochromatic source, in this case, is modeled as an arrow that spins rapidly until it is 'evaluated' at its final point. (The reason for the quotes around 'evaluated' is that this spinning is actually dependent on the time at which the photon would have left the monochromatic source, as the probability amplitudes of photons do not spin while they are in transit.) So, for example, for the probability that light will reflect off of a mirror, one sets the photon's probability amplitude spinning as it leaves the source, follows it to the mirror, and then to its final point (even for paths that do not involve bouncing off of the mirror at equal angles) and then 'evaluates' it at the final point; next, one sums these arrows (in a standard vector sum), and squares the length of the result for the probability that this photon will reflect off of the mirror. (For a simplification, the arrows representing these probability amplitudes are made an egual standard length though there are, in actuality, very minor variations.) The times these paths take are what determine the angle of the probability amplitude arrow, as they 'spin' at a constant rate (which is related to the frequency of the photon). Now, the times of the paths near the classical reflection site of the mirror will be nearly the same, so as a result the probability amplitudes will point in nearly the same direction—thus, they will have a sizable sum. As we examine the paths towards the edges of the mirror, we find that the times of nearby paths are quite different from each other, and thus we wind up summing vectors that cancel out quickly (see image). So, there is a higher probability that light will follow a near-classical reflection path than a path further out. However, a diffraction grating can be made out of this mirror, by scraping away areas near the edge of the mirror that usually cancel nearby amplitudes out—but now, since the photons would not reflect from the scraped-off portions, the probability amplitude pointing, say, to the right can have a sizable sum. Thus, this would let light of the right frequency sum to a larger probability amplitude (which, of course, then has its length squared for the probability that light will reflect from the selected region). This description of course involves many simplifications: a point source, a "surface" that light can reflect off of (thus neglecting the interactions with electrons) and so forth. However, this approximation is a reasonable one to illustrate a diffraction grating conceptually. Light of a different frequency can also use the same diffraction grating, but with a different final point. [1]
Trmwiki ( talk) 21:58, 2 October 2011 (UTC)
Since none have objected so far, I'll go ahead and post this in the main article. Feel free to change anything, of course. Anyway. Thanks! — Preceding unsigned comment added by Trmwiki ( talk • contribs) 22:00, 2 October 2011 (UTC)
The tutorial is divided in the following section: Section 1: DIFFRACTION GRATINGS ? RULED & HOLOGRAPHIC Section 2: MONOCHROMATORS & SPECTROGRAPHS Section 3: SPECTROMETER THROUGHPUT & ETENDUE Section 4: OPTICAL SIGNAL?TO?NOISE RATIO AND STRAY LIGHT Section 5: THE RELATIONSHIP BETWEEN WAVELENGTH AND PIXEL POSITION ON AN ARRAY Section 6: ENTRANCE OPTICS
It is a tutorial, by J.M. Lerner and A. Thevenon, part of the HORIBA Jobin Yvon company website, on the optics of spectroscopy. It covers: diffraction gratings - ruled and holographic; monochromators and spectrographs; spectrometer throughput and etendue; optical signal-to-noise ratio and stray light; the relationship between wavelength and pixel position of an array; and entrance optics.
This article will be very helpful on the diffraction grating page as an external link ( http://www.jobinyvon.com/SiteResources/Data/Templates/1divisional.asp?DocID=616&v1ID=&lang=) . Afrine ( talk) 14:47, 21 November 2008 (UTC)
"Diffraction gratings are also present in nature. For example, the iridescent colors of peacock feathers, mother-of-pearl, butterfly wings, and some other insects are caused by very fine regular structures that diffract light, splitting it into its component colors." Does this also apply to other iridescent surfaces found in nature, like the leaves of some plants ? If not then what is the iridescence mechanism ? 77.100.112.34 ( talk) 16:42, 10 September 2010 (UTC)
On the NASA astronomy picture of the day website, yesterday, was posted a photo of iridescent clouds, which are apparently caused by the diffraction grating phenomenon. I don't have any reliably sourced info on this, but if someone does, it may be worth adding to the article. Zaereth ( talk) 20:44, 9 February 2011 (UTC)
Can anyone find a diagram to illustrate the grating equation explanation in the "Theory of Operation" section? In particular it should show the wavefronts and/or interference pattern in relation to the angle theta_i, which is hard to visualize from the text. (As well as d,lambda of course, and a value for m.) 84.227.237.33 ( talk) 18:32, 3 April 2014 (UTC)
I don't understand what it is that is being depicted in the recently added "density plot" image. The density of what? What does the horizontal axis represent? Is the density of whatever it is represented by the colour value? It does not correspond to anything I see in the main text. -- Lambiam 11:32, 14 August 2014 (UTC)
The user who added the image has not responded and not edited for three months. I have now removed the image from the article. -- Lambiam 06:52, 17 November 2014 (UTC)
Re [1] "What kind of grating produces radial spectral like this? There should be a page about it, but this article needs a figure showing a normal linearly dispersed spectrum."
No prisms involved Andy. The Cokin #042 diffraction grating pattern is more complex than one set of straight of parallel lines : it's twenty such sets superimposed, each offset by a rotation of 9o, producing 40 discrete linear radiating spectra. Natural Philo ( talk) 00:17, 3 February 2016 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Diffraction grating. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
Sourcecheck}}
).
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 00:21, 13 December 2016 (UTC)
Important addition to Wikipedia needed: During my research on phase contrast microscopy I tumbled over the original work of F. Zernike (How I discovered Phase contrast) who said he was studying the so called "Rowland Ghosts" when he got his ingenious idea. Unfortunately the term Rowland Ghost is not classified and not yet part of the Wikipedia. It appears that the Rowland Ghosts are entangled with diffraction gratings. So please update that issue.
This article contains the (in my opinion) unrealistic statement "Diffraction colors also appear when one looks at a bright point source through a translucent fine-pitch umbrella-fabric covering". I have never seen diffraction colors through an umbrella, in contrast to when looking through fine silk fabric. An umbrella diffuses the light like frosted glass, whereas silk does not diffuse the light at all. An umbrella is opaque, whereas silk is semi-transparent. Silk and umbrellas contain 4 threads per mm, so the calculated separation between diffraction maxima is 0.13°. If the light is diffused over more than 0.13°, diffraction colors disappear. See the photo of screws seen through silk. The double contours are due to diffraction. In contrast, screws are invisible through an umbrella. Ceinturion ( talk) 18:56, 22 May 2021 (UTC)
I remember learning this long ago and have seen it for myself, yet I see no discussion of it on this Wikipedia page and have had no luck tracking down any online discussions of it after multiple Google searches. Why do/can diffraction gratings favor one side over the other, making either their left spectral patterns or their right spectral patterns brighter than the other side? 173.225.198.117 ( talk) 21:32, 22 February 2024 (UTC)
This is the
talk page for discussing improvements to the
Diffraction grating article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This
level-4 vital article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||
|
The jupiterscope is a wibbly vinyl diffraction grating that could be placed on a camera lens There are also candies with diffraction gratings pressed onto them to have vivild pure colors These are of note as the jupiterscope could make greasy glass also become a diffraction grating from the impression The candy reminds us that cheap nanoprinting on carbohydrates is possible
The dimension and period of the grooves must be on the order of the wavelength in question.
echelle gratings
A fundamental property of gratings is that the angle of deviation of all but one of the diffracted beams depends on the wavelength of the incident light.
Therefore, a grating separates an incident polychromatic beam into its constituent wavelength components, i.e., it is dispersive
When groove spacing...
Booo science club! Hooray understanding! Viva la understandionne!
Because it isn't correct. 'Dimension' is easy to understand. 'Period' and 'order' in the context of science are also straightforward, anyone with any interest whatsoever in diffraction gratings will understand these.
Agreed. I'll put up an article or expansion request.
It would take a few minutes of research for any half-intelligent person to get up to speed here. Again, if you're anything to do with science, you should know these.
Good grief, just do your homework. Nothing in this article is difficult to understand. Sojourner001 22:54, 18 January 2007 (UTC)
According to http://scienceworld.wolfram.com/physics/GratingEquation.html and some supplier's catalogs (www.thorlabs.com) the diffraction equation should be dsin(theta_incident)+dsin(theta_reflected)=m(lambda). There should be no minus sign. I'm not sure how to edit the equations, so I'll trust that someone else will do this. -- 128.196.213.163 21:59, 30 October 2006 (UTC)Anon
How are groove period and groove density related? Are they inverses of one another? The article leaves this unclear, but an inverse relation is implied when the units are compared... —The preceding unsigned comment was added by MyOwnLittlWorld ( talk • contribs) 16:39, 27 February 2007 (UTC).
I don't think an LCD can cause a diffraction pattern, and am pretty sure if it could it wouldn't look like that. Is the picture instead an example of Newton's rings, caused by the close but imperfect separation between the LCD surface and the protective plastic screen? Atropos235 19:12, 18 February 2007 (UTC)
Agreed. The color pattern in the photograph, is in no way reminiscent of the pattern created by a periodic structure (like the pixels of an lcd in this case.). Also the spacing of the pixels is too large to produce significant diffraction effects with visible light. I would guess what we are seeing has to do with the polarization of light, passing through the polarizer in the LCD screen. Transparent plastics have the property that they can rotate the polarization of light with a degree depending on how much stress is applied to the material; this effect is also wavelength dependent. This could cause different regions to reflect different colors of light. -- V. 03:36, 3 March 2007 (UTC)
Having seen similar patterns on the LCD of my own cellphone, I found that after cleaning its surface they disappeared. So, in my case, it does seem to be caused at least in part by a thin-film effect, produced by oil (from either my own body or something I handled) left on the surface by my fingers. I infer, partly from the wave-like images in the top part of the pictured LCD, that the thin-film and polarizer effects may both contribute to what we see. 71.163.224.207 ( talk) 19:25, 7 April 2016 (UTC) -- SlinkyManatee
LCD screen definitely can make a diffraction. See my posting at
Isaacto ( talk) 10:31, 31 January 2017 (UTC)
I also don't think the original photo is diffraction due to LCD. On the other hand, if LCD is not cited as an example I feel something is lost, since it is the diffraction grating that is available to about everybody, and can be easily measured and checked against the theory. 1.36.38.215 ( talk) 13:47, 2 February 2017 (UTC)
I've written a section, edit it like hell. I tried to put one of those photos as a demonstration, but couldn't get Wikipedia to be able to verify it as "suitable for Wikipedia Commons". Any hint is appreciated. 1.36.38.215 ( talk) 14:29, 3 February 2017 (UTC)
I've uploaded the photo. I think it is more to do with insufficient information I've given to the image that I can't upload it initially. Thanks for your help! And let me know if you have any comments. Isaacto ( talk) 04:46, 4 February 2017 (UTC)
What is the lines-per-inch of a CD or a DVD?- 69.87.204.209 21:02, 1 June 2007 (UTC)
Does anyone feel up to the challenge of writing something easier to understand? If I didn't already know what to expect I wouldn't understand it. RJFJR 17:16, 14 June 2007 (UTC)
It is my understanding that it isthe thin film effect that causes interference patterns in reflected light from the dataside of cd's and dvd's and that the example on teh page needs to be removed. Allywilson ( talk) 16:40, 18 November 2007 (UTC)
I have re-arranged this article, and added some new bits to make it, I hope, more comprehensible, and to have a more logical structure.
The section on 'gratings as dispersive elements' is still a bit of a mish-mash, and I will do more work on this. I don't know enough about the manufacture of gratings to do anything with this section, but I suspect it is very sketchy and imcomplete Epzcaw ( talk) 13:28, 26 May 2008 (UTC)
I believe that it is important to discuss the concept of diffraction efficiency either within this page or on a page of its own. I think it should be a section within this page. To those who don't know diffraction efficiency is what percent of the incident light is diffracted to a particular diffraction order in reflectance or transmitance (The efficiencies are generally different). Resonant gratings can be designed that for specific conditions (angle, wavelenth, polarization) the diffraction efficiency of a particular order will be 100%. Eranus ( talk) 07:44, 24 July 2008 (UTC)
This is a bit more for the physics students and not the classical way to view diffraction. Since gratings are periodic, one can use the formalism of solid state physics which deals with periodic structures on the atomic scale. Anyway a homegeneous surface can not change the momentum (propagation vector, k) parralel to the surface. This is the relation between translational symmetry and conservation of momentum. A periodic structure conserves only crystal mometnum also known as quasi momentum, it means that the momentum is conserved up to a reciprocal lattice vector K (1/peiod), so if the grating is periodic in the x direction and the structure is homogeneous in the y direction, then
where m is the diffraction order and n the refractive index in the region of diffraction (reflection or tansmition). The way form here to the grating formula is very short, all form symmetry point of view. Will be glad to hear opinions if this should be included (Of course better worded) Eranus ( talk) 07:44, 24 July 2008 (UTC)
I certainly think the description of diffraction gratings which uses QED should be included or some form of explanation using photons - it's quite important to realise that this can't just be explained using waves.
Anon. —Preceding unsigned comment added by 92.15.40.214 ( talk) 18:49, 7 August 2009 (UTC)
Hi, everyone. I'm new to this. To get the ball rolling on QED in this article, I've written up a little piece using Feynman's example in his book. However, I'm young, with much to learn in the wonderful field of quantum electrodymanics, in which I've just begun to swim—nearly all of my knowledge of it comes from Feynman's book. So please, edit the heck out of this, both in language and in content—it would be nice to see a quantum electrodynamical explanation of diffraction gratings here. Also, I'll scan the images from QED when I get the time.
QED (quantum electrodynamics) offers a derivation of the properties of a diffraction grating in terms of photons as particles. In short, QED models photons as following all paths from a source to a final point, each of which has a certain probability amplitude, which can be represented as a vector or complex number (equivalently), or as Richard Feynman simply calls them in his book on QED, "arrows". For the probability that a certain event will happen, one sums the probability amplitudes for all of the possible ways in which the event can occur, and then takes the square of the length of the result. The probability amplitude of a photon from a monochromatic source, in this case, is modeled as an arrow that spins rapidly until it is 'evaluated' at its final point. (The reason for the quotes around 'evaluated' is that this spinning is actually dependent on the time at which the photon would have left the monochromatic source, as the probability amplitudes of photons do not spin while they are in transit.) So, for example, for the probability that light will reflect off of a mirror, one sets the photon's probability amplitude spinning as it leaves the source, follows it to the mirror, and then to its final point (even for paths that do not involve bouncing off of the mirror at equal angles) and then 'evaluates' it at the final point; next, one sums these arrows (in a standard vector sum), and squares the length of the result for the probability that this photon will reflect off of the mirror. (For a simplification, the arrows representing these probability amplitudes are made an egual standard length though there are, in actuality, very minor variations.) The times these paths take are what determine the angle of the probability amplitude arrow, as they 'spin' at a constant rate (which is related to the frequency of the photon). Now, the times of the paths near the classical reflection site of the mirror will be nearly the same, so as a result the probability amplitudes will point in nearly the same direction—thus, they will have a sizable sum. As we examine the paths towards the edges of the mirror, we find that the times of nearby paths are quite different from each other, and thus we wind up summing vectors that cancel out quickly (see image). So, there is a higher probability that light will follow a near-classical reflection path than a path further out. However, a diffraction grating can be made out of this mirror, by scraping away areas near the edge of the mirror that usually cancel nearby amplitudes out—but now, since the photons would not reflect from the scraped-off portions, the probability amplitude pointing, say, to the right can have a sizable sum. Thus, this would let light of the right frequency sum to a larger probability amplitude (which, of course, then has its length squared for the probability that light will reflect from the selected region). This description of course involves many simplifications: a point source, a "surface" that light can reflect off of (thus neglecting the interactions with electrons) and so forth. However, this approximation is a reasonable one to illustrate a diffraction grating conceptually. Light of a different frequency can also use the same diffraction grating, but with a different final point. [1]
Trmwiki ( talk) 21:58, 2 October 2011 (UTC)
Since none have objected so far, I'll go ahead and post this in the main article. Feel free to change anything, of course. Anyway. Thanks! — Preceding unsigned comment added by Trmwiki ( talk • contribs) 22:00, 2 October 2011 (UTC)
The tutorial is divided in the following section: Section 1: DIFFRACTION GRATINGS ? RULED & HOLOGRAPHIC Section 2: MONOCHROMATORS & SPECTROGRAPHS Section 3: SPECTROMETER THROUGHPUT & ETENDUE Section 4: OPTICAL SIGNAL?TO?NOISE RATIO AND STRAY LIGHT Section 5: THE RELATIONSHIP BETWEEN WAVELENGTH AND PIXEL POSITION ON AN ARRAY Section 6: ENTRANCE OPTICS
It is a tutorial, by J.M. Lerner and A. Thevenon, part of the HORIBA Jobin Yvon company website, on the optics of spectroscopy. It covers: diffraction gratings - ruled and holographic; monochromators and spectrographs; spectrometer throughput and etendue; optical signal-to-noise ratio and stray light; the relationship between wavelength and pixel position of an array; and entrance optics.
This article will be very helpful on the diffraction grating page as an external link ( http://www.jobinyvon.com/SiteResources/Data/Templates/1divisional.asp?DocID=616&v1ID=&lang=) . Afrine ( talk) 14:47, 21 November 2008 (UTC)
"Diffraction gratings are also present in nature. For example, the iridescent colors of peacock feathers, mother-of-pearl, butterfly wings, and some other insects are caused by very fine regular structures that diffract light, splitting it into its component colors." Does this also apply to other iridescent surfaces found in nature, like the leaves of some plants ? If not then what is the iridescence mechanism ? 77.100.112.34 ( talk) 16:42, 10 September 2010 (UTC)
On the NASA astronomy picture of the day website, yesterday, was posted a photo of iridescent clouds, which are apparently caused by the diffraction grating phenomenon. I don't have any reliably sourced info on this, but if someone does, it may be worth adding to the article. Zaereth ( talk) 20:44, 9 February 2011 (UTC)
Can anyone find a diagram to illustrate the grating equation explanation in the "Theory of Operation" section? In particular it should show the wavefronts and/or interference pattern in relation to the angle theta_i, which is hard to visualize from the text. (As well as d,lambda of course, and a value for m.) 84.227.237.33 ( talk) 18:32, 3 April 2014 (UTC)
I don't understand what it is that is being depicted in the recently added "density plot" image. The density of what? What does the horizontal axis represent? Is the density of whatever it is represented by the colour value? It does not correspond to anything I see in the main text. -- Lambiam 11:32, 14 August 2014 (UTC)
The user who added the image has not responded and not edited for three months. I have now removed the image from the article. -- Lambiam 06:52, 17 November 2014 (UTC)
Re [1] "What kind of grating produces radial spectral like this? There should be a page about it, but this article needs a figure showing a normal linearly dispersed spectrum."
No prisms involved Andy. The Cokin #042 diffraction grating pattern is more complex than one set of straight of parallel lines : it's twenty such sets superimposed, each offset by a rotation of 9o, producing 40 discrete linear radiating spectra. Natural Philo ( talk) 00:17, 3 February 2016 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Diffraction grating. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
Sourcecheck}}
).
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 00:21, 13 December 2016 (UTC)
Important addition to Wikipedia needed: During my research on phase contrast microscopy I tumbled over the original work of F. Zernike (How I discovered Phase contrast) who said he was studying the so called "Rowland Ghosts" when he got his ingenious idea. Unfortunately the term Rowland Ghost is not classified and not yet part of the Wikipedia. It appears that the Rowland Ghosts are entangled with diffraction gratings. So please update that issue.
This article contains the (in my opinion) unrealistic statement "Diffraction colors also appear when one looks at a bright point source through a translucent fine-pitch umbrella-fabric covering". I have never seen diffraction colors through an umbrella, in contrast to when looking through fine silk fabric. An umbrella diffuses the light like frosted glass, whereas silk does not diffuse the light at all. An umbrella is opaque, whereas silk is semi-transparent. Silk and umbrellas contain 4 threads per mm, so the calculated separation between diffraction maxima is 0.13°. If the light is diffused over more than 0.13°, diffraction colors disappear. See the photo of screws seen through silk. The double contours are due to diffraction. In contrast, screws are invisible through an umbrella. Ceinturion ( talk) 18:56, 22 May 2021 (UTC)
I remember learning this long ago and have seen it for myself, yet I see no discussion of it on this Wikipedia page and have had no luck tracking down any online discussions of it after multiple Google searches. Why do/can diffraction gratings favor one side over the other, making either their left spectral patterns or their right spectral patterns brighter than the other side? 173.225.198.117 ( talk) 21:32, 22 February 2024 (UTC)