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"Diffractive Optics" redirects to this article. Diffractive Optics is a technique for making smaller and lighter lenses. It has nothing whatsover to do with the content of this article. 86.147.237.233 ( talk) 12:40, 17 March 2012 (UTC)
In this section, it is mentioned "Hence, the smaller the output beam, the quicker it diverges". Here, does "smaller" mean a smaller size or something else? Hopefully someone can help me with this question, thanks! AlexHe34 ( talk) 15:14, 30 March 2012 (UTC)
I have fixed few other things here. Laser mirror is a resonator, not an aperture. And the laser beam is not always a fundamental mode (in fact, almost never). — Preceding unsigned comment added by Khrapkorr ( talk • contribs) 20:30, 10 February 2015 (UTC)
You write: "Thomas Young performed a celebrated experiment in 1803 demonstrating interference from two closely spaced slits.[10]"
If you actually read the Bakerian lecture you reference [10] you will see that he does not discuss the celebrated double-slit experiment, nor is the diagram you print in that lecture. the only place Young mentions the experiments is in his popular lectures before Royal Institution (pub. 1807). The diagram is in fact from his lecture on hydraulics, not light, and although he describes a two-slit experiment, he never claims he actually did it. Furthermore the wavelengths he quotes for the wavelengths of light is from the Newton's rings experiment. There is no clear evidence that Young ever performed the experiment.
Tony Rothman
explain me the double slit diffraction ( Radhika thakur ( talk) 15:19, 21 April 2012 (UTC))
I'm posting this here with the hope that a definitive answer could be included in an amended version of the main article. It was once explained to me in class when I was an undergraduate that single-slit diffraction could be understood in terms of the Heisenberg uncertainty principle. The argument goes as follows: Imagine an incident plane wave of light at wavelength "λ" approaching a 1-dimensional slit aperture from the left, which I will define as the "x" direction. The slit is of height "d" along the "y" direction, and for simplicity's sake is infinite along the z direction. Light must pass through the slit in the form of photons, and the Heisenberg uncertainty principle places limits on these photons' momenta. Specifically, we know that as a photon passes through the slit, its vertical position is known to within an uncertainty "d/2," so the vertical component of momentum, "p_y", is only defined to within a precision of hbar / d.
Now, because the incident light was coming in with wavelength λ, we know that each photon’s total momentum must be 2 π hbar / λ. We can combine the two relationships to give the following relation,
To within some factors of π and 2 that can probably be explained away by the specific geometry of the slit, this is exactly the width of the central peak in Fraunhofer diffraction.
My question is this: What happens when the slit becomes narrower than lambda / (2 pi)? That is to say, what happens when the slit becomes so narrow that a photon passing though it must acquire an uncertainty in transverse momentum which is greater than the photon’s total momentum was to begin with? Two possibilities come to mind:
Thanks in advance for any thoughts. Csmallw ( talk) 04:57, 29 June 2013 (UTC)
When you look at "point-like" lights through a rectangular grid, you see four diffraction spikes around each light. This is called a Don Quixote's Windmill, and that should be a heading that re-directs to this page. The best and most common example of this is looking at outside street lighting through an insect screened window or door at night time. Amazingly perceptive yet totally simple spectrographic analysis can be performed just from this phenomenon alone. For example, the difference between incandescent and metal-vapour emission lighting (such as sodium)is immediately obvious. Other examples are looking through lace or sheer curtains. I am happy to take and post some images and do a brief write-up of all of this, but someone else would have to do the redirect. 121.216.26.225 ( talk) 09:54, 9 November 2014 (UTC)
OK, then, will do. My WIkiactivity is very erratice so it will take some time. — Preceding unsigned comment added by 121.216.207.197 ( talk) 10:52, 10 November 2014 (UTC)
Err, no these bright rings are caused by atmospheric REFRACTION. If you follow the link it even warns you not to confuse the two. 121.216.26.225 ( talk) 09:58, 9 November 2014 (UTC)
This image on the front page is named as "Laser Interference" by the uploader. Could the author actually upload a interference pattern rather than diffraction pattern? As far as I know, it's possible to produce such pattern with Michelson and Morley setup. — Preceding unsigned comment added by Mywtfmp3 ( talk • contribs) 07:04, 8 September 2015 (UTC)
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This
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"Diffractive Optics" redirects to this article. Diffractive Optics is a technique for making smaller and lighter lenses. It has nothing whatsover to do with the content of this article. 86.147.237.233 ( talk) 12:40, 17 March 2012 (UTC)
In this section, it is mentioned "Hence, the smaller the output beam, the quicker it diverges". Here, does "smaller" mean a smaller size or something else? Hopefully someone can help me with this question, thanks! AlexHe34 ( talk) 15:14, 30 March 2012 (UTC)
I have fixed few other things here. Laser mirror is a resonator, not an aperture. And the laser beam is not always a fundamental mode (in fact, almost never). — Preceding unsigned comment added by Khrapkorr ( talk • contribs) 20:30, 10 February 2015 (UTC)
You write: "Thomas Young performed a celebrated experiment in 1803 demonstrating interference from two closely spaced slits.[10]"
If you actually read the Bakerian lecture you reference [10] you will see that he does not discuss the celebrated double-slit experiment, nor is the diagram you print in that lecture. the only place Young mentions the experiments is in his popular lectures before Royal Institution (pub. 1807). The diagram is in fact from his lecture on hydraulics, not light, and although he describes a two-slit experiment, he never claims he actually did it. Furthermore the wavelengths he quotes for the wavelengths of light is from the Newton's rings experiment. There is no clear evidence that Young ever performed the experiment.
Tony Rothman
explain me the double slit diffraction ( Radhika thakur ( talk) 15:19, 21 April 2012 (UTC))
I'm posting this here with the hope that a definitive answer could be included in an amended version of the main article. It was once explained to me in class when I was an undergraduate that single-slit diffraction could be understood in terms of the Heisenberg uncertainty principle. The argument goes as follows: Imagine an incident plane wave of light at wavelength "λ" approaching a 1-dimensional slit aperture from the left, which I will define as the "x" direction. The slit is of height "d" along the "y" direction, and for simplicity's sake is infinite along the z direction. Light must pass through the slit in the form of photons, and the Heisenberg uncertainty principle places limits on these photons' momenta. Specifically, we know that as a photon passes through the slit, its vertical position is known to within an uncertainty "d/2," so the vertical component of momentum, "p_y", is only defined to within a precision of hbar / d.
Now, because the incident light was coming in with wavelength λ, we know that each photon’s total momentum must be 2 π hbar / λ. We can combine the two relationships to give the following relation,
To within some factors of π and 2 that can probably be explained away by the specific geometry of the slit, this is exactly the width of the central peak in Fraunhofer diffraction.
My question is this: What happens when the slit becomes narrower than lambda / (2 pi)? That is to say, what happens when the slit becomes so narrow that a photon passing though it must acquire an uncertainty in transverse momentum which is greater than the photon’s total momentum was to begin with? Two possibilities come to mind:
Thanks in advance for any thoughts. Csmallw ( talk) 04:57, 29 June 2013 (UTC)
When you look at "point-like" lights through a rectangular grid, you see four diffraction spikes around each light. This is called a Don Quixote's Windmill, and that should be a heading that re-directs to this page. The best and most common example of this is looking at outside street lighting through an insect screened window or door at night time. Amazingly perceptive yet totally simple spectrographic analysis can be performed just from this phenomenon alone. For example, the difference between incandescent and metal-vapour emission lighting (such as sodium)is immediately obvious. Other examples are looking through lace or sheer curtains. I am happy to take and post some images and do a brief write-up of all of this, but someone else would have to do the redirect. 121.216.26.225 ( talk) 09:54, 9 November 2014 (UTC)
OK, then, will do. My WIkiactivity is very erratice so it will take some time. — Preceding unsigned comment added by 121.216.207.197 ( talk) 10:52, 10 November 2014 (UTC)
Err, no these bright rings are caused by atmospheric REFRACTION. If you follow the link it even warns you not to confuse the two. 121.216.26.225 ( talk) 09:58, 9 November 2014 (UTC)
This image on the front page is named as "Laser Interference" by the uploader. Could the author actually upload a interference pattern rather than diffraction pattern? As far as I know, it's possible to produce such pattern with Michelson and Morley setup. — Preceding unsigned comment added by Mywtfmp3 ( talk • contribs) 07:04, 8 September 2015 (UTC)
Hello fellow Wikipedians,
I have just added archive links to one external link on
Diffraction. Please take a moment to review
my edit. If necessary, add {{
cbignore}}
after the link to keep me from modifying it. Alternatively, you can add {{
nobots|deny=InternetArchiveBot}}
to keep me off the page altogether. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true to let others know.
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
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source check}}
(last update: 18 January 2022).
Cheers.— cyberbot II Talk to my owner:Online 08:53, 27 February 2016 (UTC)