Diffraction Definition and 1000 Threads

Hi, Today I was told that phase and amplitude on the screen in a far field of a mask consisting of hole are more or less the same. So, I wanted to check myself, but didn't find any resource for this. All the resources are, as usual, talk about intensity distribution in the Fourier domain, but...

Homework Statement A laser is a light source that emits a diffraction-limited beam (like waves diffracting through a wide slit) of diameter 2 mm. Ignoring any scattering due to the Earth's atmosphere, calculate how big a light spot would be produced on the surface of the moon, 240,000 miles...

I am quite aware of the effect of slit width and wavelength in a single-slit diffraction pattern. However, my teacher has never touched on the effect of a source moving towards or away from the slit. Neither can I find any satisfactory or comprehensible response to this phenomenon. While my...

Homework Statement (see attached problem) Homework Equations (see attached problem) The Attempt at a Solution So assuming the area of the hole is circular, halving its diameter, will decrease its area by a factor of 16. Therefore LI will be I/16? However in the solution (see attached...

Homework Statement I have a question on a practice midterm my professor sent out. I would ideally ask him, but I won't see him until itake my midterm. Instead I am attaching the question and solutions at attachments. THe question of interest is in the attachment "physics question" and the...

I have a confusion regarding interference and diffraction phenomenon, I will be glad if you can post a video or something about interference and diffraction basics. I don't have meaningful concept over their differences. [Mentor's Note: Thread moved to General Physics and thread title edited]

Homework Statement What would the focal length be of a diffraction grating if the set up is a laser placed 1 m from the 0 order diffraction? Would it be the distance from the grating to the laser or the distance from the grating to the image? Homework Equations 1/f = 1/o + 1/i Rd = [Df]-1...

I know light has wave particle duality, I understand these two points very well, 1. Light moves as a probability function, taking all the possible paths at once. The alternate paths cancel themselves out, resulting in a particle-like combined motion. 2. When relatively close to an edge, some...

Hello, I have a question: let's assume that some photons are passing ~10m pupil, like in largest telescopes. Are they EXACTLY identical AFTER passing, than before? Or is there some lost of infromation becouse most part of their wavefront is cutted off and we only register ~10m part of it (from...

Lets say I have three surfaces, one with pattern A, one with pattern B and the third with A and B overlapped. Will the diffraction pattern be a simple addition of the diffraction patterns from A and B?

Hello, My name is Thibaut, I am a student in physics and I currently struggling with something that some of you might find obvious. I did an experiment with a laser 650nm passing through a 2D squared grid. The light interferes and diffracts and a photomultiplier collect only the central spot...

Why can a laser only be focussed to within its wavelength? It says due to it being diffraction limited, what about focussing lenses and mirrors they don't involve diffraction. Please explain

interference is a superposition of two waves coming two slits... diffraction is a superposition of a family of waves from a single slit.. then how the fringes formed during double slit experiment is actually a superposition of single-slit diffraction from each slit and the double-slit...

I would like to know what the dots are. This reminds me of X-ray diffraction, but I am imaging a sphere of liquid on the end of a microcapillary nozzle (2um inner diameter glass nozzle with sputtered gold outer coating on nozzle). I am taking a picture of a small glass nozzle with a metal...

Hi all, I have a small misunderstanding about the energy conservation in diffraction from 2 slits. First, I understand the energy conservation of interference from 2 slits. If intensity from each slit is I, then I have intensity of 2I after slits plane. Interference is given by: So at bright...

Homework Statement In the experiment of Davisson and Germer (a) show that the second- and third-orderdiffracted beams cannot occur and (b) find the angle at which the first-order diffracted beamwould occur if the accelerating potential were changed from 54 to 60 V. (c) What...

What is the material that doesn't diffract x rays ?

If plane waves of light in a vacuum are incident on a slit that is not stationary with respect to the frame of reference, but it is moving either backwards or forwards with a certain speed, what will the diffraction "field" look like?

In the emission theory of light, light waves can move at any speed. We can still apply the Doppler effect, but to the best of my knowledge, only the frequency changes, not the wavelength. The pattern for a diffraction grating only depends on the wavelength right? And we have observed...

Hi everybody, At wiki, I was astonished to read this about diffraction of light : "In Quantum Mechanics, it is a remarkable fact that the mechanism of diffraction is based on radiating particles of a medium, while quantum mechanical waves have no transmitting medium. As being part of the...

Homework Statement Monochromatic electromagnetic radiation of wavelength λ nm falls on double slits, creating a diffraction pattern on a screen L m away, Suppose now that the distance between the slits begins to increase at a constant rate: dd/dt = x μm/s. Assume that everything else...

Why does a large number of identical particles randomly distributed produce a diffraction pattern same as that of a single particle?

Homework Statement Estimate the diffraction angle. The spectrometer is made from rolling up a 30cm long piece of cardboard into a tube. Duct tape is placed over one end, and a thin slit is made. The other end has a diffraction grating held in place. I look through the diffraction grating and...

Homework Statement A diffracting grating casts a pattern on a screen located a distance L from the grating. The central bright fringe falls directly in the center of the screen. For the highest-order bright fringe that hits the screen, m=x, and this fringe hits exactly on the screen edge. This...

Hello! I would be very happy if you could lend me a helping hand with the following problem. :) 1. Homework Statement We know that a CD is read with a laser with a wavelenght of λ = 1 μm. a) Estimate the data stored on the CD. b) We know that the CD contains 80 minutes of sound. How fast is it...

Homework Statement A thin piece of metal foil of thickness 0.0700 mm separates one end of two pieces of optically flat glass. The top sheet of glass is 12.0 cm long. Light of wavelength 529 nm is normally incident on the glass. How many interference fringes are observed per cm in the reflected...

I recently learned about the so called "diffraction" grating. In most textbooks I have seen, it is described as multiple slits setup, with really narrow slits. It is sometimes said that the width of the slits is much less than the wavelength of the light going through it. Where is the...

Homework Statement You shine a red (λ = 650 nm) laser beam and a green (λ = 532 nm) laser beam at a diffraction grating that has 400 slits/mm to create an interference pattern on a wall 2.30 m from the grating. If the two lasers are directly on top of each other, how far apart are the two m = 1...

In the double-slit diffraction experiment, two interferences are observed simultaneously : diffraction interference from each single-slit, and double-slit interference (where in the double-slit interference, diffraction is ignored because we considered theoretical slits way smaller than...

Hey! I have a very unusual question. It is about using ImageJ to analyze diffraction patterns from TEM. 1. Homework Statement To calculate lattice parameter I need Miller Indices from planes I can recognize in the picture, wavelength of electrons and camera length. In our instructions for...

Homework Statement [/B] Hi there! This is a question from a practice problem sheet I got from the lecturer of my Condensed Matter 1 course. Below are the normal vectors to the {111} and {112} lattice planes: Homework Equations [/B] Bragg Condition: \begin{equation} n \lambda = d \sin...

I have found lots of forum threads on this but I still can't see the connection between wavelength and diffraction. Here is a picture I found: If you increase the wavelength then all is this will do is just increase the time between the crests that arrive and I don't see how that can have...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >[/color] Hi guys, I have a question here which I'm struggling to do and perhaps you could help ; Monochromatic electromagnetic radiation with wavelength λ from a distant source passes through a...

Hello all, Guys, I just pointed out that I actually lacking in somewhere in the understanding of the phenomenon of diffraction of light, of which I am aware from no less than 10 years. Recently I revised Huygens wave theory of Light and studied in what ways Newton criticize it. At one of the...

1. Homework Statement Homework Equations dsinθ=nλ The Attempt at a Solution I chose D, but I can't seem to see why the number of orders changes. There are more lines per metre, so distance between slits decreases, hence sinθ would increase, which means θ increases too. But this would only...

Homework Statement Is diffraction at a maximum when the width of the gap is similar in length to the wavelength of the light? (ie. W ≈ λ, where w=width) Or is it a maximum when the width is smaller than the wavelength? (i.e W < λ)Thanks for the help!Homework Equations n/a (this is a homework...

I read in texts that when a rays of light are diffracted from a straight edge, the phenomenon can be explained using the half period zones. The things that is confusing me is this: "Odd number of half period zones, if exposed, lead to a bright fringe. Even number of half period zones exposed...

In a single slit diffraction setting, if the width of a slit is not much wider than the diameter of a particle such as a photon or an electron, would we still see diffraction bands? If so, is the number of bands / spots you see on the screen across is finite? I am a little confused by the...

Homework Statement A grating has a line density of 1010 cm−1, and a screen perpendicular to the ray that makes the central peak of the diffraction pattern is 2.5 m from the grating. If light of two wavelengths, 590 nm and 680 nm, passes through the grating, what is the separation on the (flat)...

I was working on derivation to find the witdh of principle maxima in n slit diffraction Angular width=2Δθm=2λ/(Ndcosθm) Where d:distance between slits θm:angle at which mth order principle maxima is present. N:no. Of slits #in the diagram given below why the minima just adjacent to mth...

if I'm given grating width=5cm ,slits of width=0.0001cm separated by a distance of 0.0002cm how many order would be observable at λ=5.5 x 10-5cm? calculate the width of principle maximum? please tell me the approach to do this problem

Hi guys, I'm doing an into to diffraction tomorrow, explaining what diffraction is - so light or sound waves spreading out as they pass through a gap, and when it occurs - so it is a maximum when gap size is comparable to wavelength. However I just want to be prepared to answer why this is the...

This question came up in the biology section https://www.physicsforums.com/threads/explain-different-types-of-light-microscopy.833990/. Q1: The longer the wavelength of a wave, the more easily it bend around an obstacle. I do understand the mathematics, but is there any intuition for it? Q2A...

Q1. I do not understand why the light has to bend inorder to undergo refraction. My teachers have explained me that, light bends due to the change in velocity. If I change the velocity of a car by half it's original value, I don't find the cars path changing. It does not seem to make sense to...

I'm reading this tutorial on instructables for implementing the classical double-slit experiment. I've also read this thread for information which contains a very nice answer from @BruceW but still not resolves my confusion about the "sizes". First of all I'd like to make a distinction between...

To increase the resolution of an instrument, smaller wavelength and larger aperture is desirable. It is mentioned in some textbooks that the "effective" diameter of a telescope can be increased by using arrays of smaller telescopes. I just wonder why it is possible because every telescope is...

In explaining x-ray diffraction of crystals, usually the approach is to consider the atoms absorb radiation and scatter it, at some angles constructive interference occur and bright spots can be observed. It seems that it is different from the diffraction of slits or gratings because in these...

In finding the angle for the mth dark fringe of single slit diffraction using Huygen's principle, they usually split the slit into equal portions. For example, to find the first dark fringe the slit is split into two equal spacings and if the path difference between the edge and the middle point...

Homework Statement Homework Equations dsinθ=nλ IαA2 The Attempt at a Solution I chose D because I thought that D gives the max intensity since the amplitudes superimpose over a smaller area. But the answer is C. I can't see why.

This may be a little of a stupid question. But I was looking at a diagram describing Bragg's Law of Diffraction. and I was like...how can an interference happen if wave beam C and wave beam C' are hitting different points on the detector screen?! they are not hitting the same point on the...