# What is Grating: Definition and 259 Discussions

A grating is any regularly spaced collection of essentially identical, parallel, elongated elements. Gratings usually consist of a single set of elongated elements, but can consist of two sets, in which case the second set is usually perpendicular to the first (as illustrated). When the two sets are perpendicular, this is also known as a grid (as in grid paper) or a mesh.

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1. ### I Grating Resolving Power of Laser Beams with Gaussian Distribution

All resources I’ve found for grating resolving power assume uniform distribution on the grating and produce airy disks. Resolvance is determined by the Rayleigh criterion where the peak of one wavelength is at the minima of the adjacent one. This definition doesn’t seem applicable for Gaussian...
2. ### Number of bright fringes given by diffraction grating on a screen

(1) In the book I am using the separation of bright fringes is indicated as being ##\Delta y=\frac{\lambda}{d}##, where ##d## is the separation of the slits so on a screen of width ##W## I would see ##\frac{W}{\frac{\lambda}{\frac{1}{N}}}## bright fringes. I don't see why the text of the...
3. ### A Diffraction of spherical wave by plane grating

Textbook examples usually involve a plane monochromatic wave that is diffracted by a plane grating. If one places an ideal focusing lens behind the grating one will get a diffraction pattern in the back focal plane of the lens. The geometric size of this diffraction pattern is proportional to...
4. ### Question on Resolving Power of Diffraction Grating

I have doubts about my work for the second part of the question, where I am asked if resolution will be possible or not. For the first part, I calculated No. of lines N=6.43*10^2 lines/cm For the second part, I have attached below a snapshot of my neatly written work. I request a PF member to...
5. ### I Umbrella fabric and diffraction pattern

It is sometimes said that a distant street lamp seen through a dark coloured umbrella fabric appears like dotted diffraction pattern, as in figure A. However, I have tried several umbrellas but all of them produce a blurred cross, as in figure B. The umbrella fabric superficially looks like a...
6. ### Calculating the Number of Lines for a Diffraction Grating

A spectral line of wavelength λ = 4,750˚A is actually a doublet, of separation between the lanes 0, 043˚A . a) which is the smallest number of lines a diffraction grating needs to have to separate this doublet in the 2nd order spectrum? To be honest, i don't know what to do. I first thought...
7. ### Problem on Diffraction Grating and Laser Crystallography

First question: When shining a laser (##\lambda = 630nm##) through a 2D crystal, diffraction patterns are observed. Why? Possible reasons: 1. Atoms and the space between them act as diffraction gratings. 2. Bragg Diffraction, although in this case the pattern would be observed on the same...
8. ### I Wavelength and size of holes or grating

Could someone explain to be the reason why size of the hole or grating in the case of Faraday cage is what determines if the screen or grating is opaque or transparent? I'm pretty sure it has something to do with interference patterns in classical physics. Thank you all in advanced.
9. ### The sources of error in a diffraction grating experiment

In a diffraction grating experiment, what can be the sources of error and also what effect do these sources have on the unknown quantity (wavelength) in the experiment?
10. ### Grating element of an acoustic grating

I was reading a pdf on acoustic grating for my practicals when I saw that the grating element of an acoustic grating is equal to the wavelength of the sound wave. I also checked a few other sources and got the same. I do not understand why. I know that for an acoustic wave, the standing wave...
11. ### A diffraction grating formed by parallel adjacent tracks on a CDROM

(d)sin(40.6)=(475*10^-9)(1) d=730*10^-9 (m) prof says answer is 1460*10^-9 (m) tho
12. ### Photographing diffraction grating interference patterns

If I direct a laser pointer onto a diffraction grating and place a screen beyond it, I see a diffraction pattern - a line of dots - as expected. If I move the screen further away from the grating, the distance between the dots increases - again as expected. If I place a camera where the screen...
13. ### Is the diffraction grating formula wrong?

So, two wave fronts leave adjacent "slits" in a grating and head for a screem When they get to a point of local maximum, they will have interfered constructively, and so they must be in phase. Therefore the path different will be a whole multiple of the wavelenth. People routinely draw a right...
14. ### Measuring the Distance between the Fringes of a Diffraction Grating

I have been preparing for a physics practical on diffraction. More specifically, we will use a CD as a transmission grating (by peeling off the reflective layer), and measure the distance between the fringes for a specific distance between the CD and the viewing wall. However, it is unclear...
15. ### Diffraction Grating: Possible variables for Experiment

For my High School Physics course, I have been tasked to design an experiment investigating the properties of a CD diffraction grating, and we MUST make a graph. Unfortunately, we only have two lasers of different wavelength, so changing the wavelength and measuring ##theta## would be a bad...
16. ### Double Diffraction Grating

Here is my thinking: Let's replace the second diffraction grating with a screen. Then, after passing through the first grating, I would expect there to be an interference pattern on the screen. Depending on the distances between the first grating and second, I could have several difference...

18. ### Varying thickness diffraction grating

I know that a plane wave going through a slit becomes a spherical wave because of a Huygens-Fresnel principle. Can someone explain to me why a plane wave splits into many plane waves with different directions when going through a plate with varying thickness? Can someone explain me this image?
19. ### Diffraction Grating Vs Double-Slit: Small angle Approx.

Homework Statement In double slit interference , the angle between the center bright fringe and the path length (aka the angle used to find the path length difference) can be approximate as a small angle. However, we cannot assume the angles of bright fringes due to diffraction gratings are...
20. ### Angle relationships of a blazed diffraction grating

I am trying to understand how a blazed diffraction grating works and came across a deduction I don't understand. I believe that you don't need to know much about optics to answer this question as it is more geometry related. I have the diagram below of a diffraction grating with all the relevant...
21. ### Transmission grating Nλ=dsinθ

Homework Statement This is a question we have been doing at school. The answer is C. I think A is correct as well. Homework Equations I have used nλ=dsinθ and put in test values. I guess I should be able to do this by just 'inspecting the question' but the sin confused me. So I put in some...
22. ### Find λ of light using a laser beam and a diffraction grating

1. What is the advantage of using class 2 laser light? I would really appreciate if reference source is also given!Homework Equations Not needed.[/B]The Attempt at a Solution Well, I thought that using monochromatic light would made it easier to measure the distance between fringes. And also...
23. ### Optics - Diffraction grating

Homework Statement The Attempt at a Solution Hi All! This is probably going to have a very simple answer. I'm stuck on question (b)(ii). The only equation I can find with the ruling width in it is the one shown and I can't find a way to calculate is as I don't know Beta. Thanks
24. ### A level physics doubt about a Diffraction grating

Homework Statement Monochromatic light of wavelength 690nm passes through a diffraction grating with 300 lines per mm, producing a series of maxima on a screen. What is the greatest number of maximas that can be observed? A) 4 B) 5 C) 8 D) 9 Homework Equations n*wavelength = d*sin x The...
25. ### Reflection Grating: How Does it Diffract?

How a reflection grating works as diffraction source?
26. ### How does the diffraction grating in Canadian currency work?

Hi, This is my first post so apologies if I'm not clear enough or if I am posting in the wrong place. I am doing my 3rd year project at university and I am creating diffraction gratings. My supervisor shown me a Canadian note and if you shine a laser through the maple leaf it will shine on the...
27. A

### Single Slit and Diffraction Grating Formulas

Hi everyone. I am having some difficulty understanding the formulas of single slit diffraction and diffraction gratings. This is partly because the formulas that I have been given in class do not reflect what I have found online entirely. As we know, the formula for single slit destructive...
28. A

### Diffraction Grating and White Light Problem

Homework Statement White light containing wavelengths from 400 nm to 750 nm falls on a grating with 6000 lines/cm. How wide is the first-order spectrum on a screen 2.0 meters away Homework Equations dsinθ=mλ for constructive interference dsinθ=(m+1/2)λ for destructive interference Δx = λL/d...
29. ### Grating and slits problem 28 from 9702_s17_qp_13.pdf

I can exclude B because B shows maxima, but I do not know how to exclude A and D. These are the equations for the diffraction grating and the double-slit experiment: dSin(A) = nL DL = ax It seems that this problem is about the combination of both. C is probably the correct answer...
30. ### Maxima in a diffraction grating

Homework Statement A diffraction grating is made up of slits of width 300 nm with separation 900 nm. The grating is illuminated by monochromatic plane waves of wavelength l 600 nm at normal incidence. How many maxima are there in the full diffraction pattern? Homework Equations mλ = dsinθ The...
31. ### Diffraction grating problem

Homework Statement Yellow sodium light, which consists of two wavelengths, λ_1 =589.0 nm and λ_2 = 589.89 nm, falls on a 7500 lines/cm diffraction grating. Determine (a) the maximum order m that will be present for sodium light, (b) the width of grating necessary to resolve the sodium lines...
32. ### Diffraction Grating - all visible light?

Homework Statement Find the smallest grating spacing that let's you see the entire visible spectrum. 400nm to 700nm comprises the visible light spectrum. no other information is given. Homework Equations nλ=d sin θ The Attempt at a Solution I am not sure how to start as all i have been given...
33. ### Diffraction Grating and Visible Light

Homework Statement "You're using a diffraction grating o view the 400 to 700 nm visible spectrum. Suppose you can see the spectrum through the third order. a) Show that the first and second order spectra never overlap regardless of grating spacing. b) show that the second and third order...
34. ### Diffraction grating problem involving Snell's Law

Homework Statement A 600 line/mm diffraction grating is in an empty aquarium tank. The index of refraction of the glass walls is [n][/glass] = 1.50. A helium-neon laser (lambda=633 nm) is outside the aquarium. The laser beam passes through the glass wall and illuminates the diffraction grating...
35. ### An experiment using a diffraction grating with

Homework Statement An experiment using a diffraction grating with a monochromatic light source is performed to create an interference pattern on a screen. Consider the following changes: I. Increase the line density of the grating. II. Decrease the frequency of the source. III. Increase...
36. ### Optics: dispersive power of diffraction grating

Homework Statement Hi everybody! Here is the problem I am trying to solve: a) A source illuminates a grating in a spectroscopical element so that the principal maxima appear as thin bright bands (therefore the name "spectral lines"). Show that the angular width ##\Delta \theta## of such a...
37. ### Diffraction Grating Question, Dispersion and Resolving

Homework Statement One diffraction grating has 9600 lines uniformly spaced over a width of 3cm, it is illuminated by light from a mercury vapour discharge. The other has 5000 lines/cm and is a 3.5cm grating, this one is used in the second order to resolve spectral lines close to 587.8002 nm...
38. ### Diffraction Grating wavelength

Homework Statement A) Find the diffraction order from the grating that has an angle of incidence of 40 degrees and a diffraction angle of 20 degrees. The wavelength of incident light is 500nm and the spacing between the grooves on the grating are 5 micrometers B) If I want to selectively emit...
39. ### How to find theta in a mutiple slit question

Homework Statement A diffraction grating with 14100 lines per 2.54 cm (i.e., per in.) is used to view the visible spectrum from a Hydrogen gas excited by an electrical discharge. At what angle from the beam axis will the first order peak for the red photons with wavelength of 0.656 μm occur...
40. ### Solving Diffraction Grating Angle: Can it be 90°?

You know when you have diffraction gratings, you have to measure the angle between center and first order/maxima right? My question is: can the angle be 90°? Or is it always less than that? d sin θ = nλ Thank you!
41. ### Calculating the Number of Lines on a Diffraction Grating

Homework Statement A diffraction grating gives a second-order maximum at as angle of 31° for violet light (λ = 4.0 × 10^2 nm). If the diffraction grating is 1.0 cm in width, how many lines are on this diffraction grating? Homework Equations d = (m)(λ)/sinθm The Attempt at a Solution d =...
42. ### The Diffraction Grating (Grade 12 Physics)

Homework Statement Do the maxima created by a diffraction grating all have the same intensity? Explain. Homework Equations mλ = wsinθ (?) The Attempt at a Solution According to the back of my textbook (Nelson Physics 12), the answer is no. I believe the answer may have to do with the fact...
43. ### Linearly Chirped Fiber Bragg Grating group delay

Homework Statement Here is my problem : I want to know where does group delay equation come form? Homework Equations As I checked reference 21 it only indicates The Attempt at a Solution I'm following how can I start and solve this problem
44. ### Electron Velocity Diffraction Grating Problem

Homework Statement Suppose that visible light incident on a diffraction grating with slit distance (space) of $0.01*10^{-3}$ has the first max at the angle of $3.6^{o}$ from the central peak. Suppose electrons can be diffracted with this same grating, which velocity of the electron would create...
45. ### Single-sit vs. Double-slit vs. Diffraction grating

Homework Statement Briefly state one characteristic of single-slit /double-slit/diffraction grating interference pattern that allow you to clearly distinguish one from the others. Homework Equations NoneThe Attempt at a Solution Single-slit: Taller, broader central maximum.Double-slit: More...
46. ### Rayleigh criterion (two wavelengths) + diffraction grating

Homework Statement "A source emits light with two monochromatic components of wave-lengths λ1 = 510.50 nm and λ2 = 510.90 nm. Using the Rayleigh criterion, find the minimum number of slits of a grating that must be illuminated by a beam from the source in order to resolve these components."...
47. ### Focal length of diffraction grating for recip. dispersion

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...
48. ### MATLAB Center Wavelength of Fiber Bragg Grating Filter

I would like to locate the center wavelength of a FBG notch filter in MATLAB, but I'm having trouble getting an answer within 0.01nm of the correct wavelength. So far I've tried using a quadratic fit with MATLAB, but that is too dependent on the amount of data points to the left and right of...
49. ### Diffraction Grating Relationship Question

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...
50. ### Diffraction Grating Homework: Find the Distance of Bright Fringes

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...