Order of Diffraction Explained: Animation & Detailed Explanation

[dima_tr]

Hi.

I cannot understand what the order of diffraction means.

Could anybody give me some link with animation or detailed explanation?

I do not understand why it should be integer to create constructive interference?

 

[Andy Resnick]

Diffraction order can refer to a couple concepts. In dispersive optical systems (e.g. a spectrometer), light diffracting off a grating is split into multiple orders (or rainbows) because if sin(x) is a solution to the scattering problem, so is sin(2x) and sin(3x), etc.

Section 2.2 may be relevant to you:
http://gratings.newport.com/information/handbook/chapter2.asp

 

[Redbelly98]

A simple answer is: to have constructive interference, the path difference of adjacent "rays" must be an integer multiple of the wavelength. Whatever that multiple is, is the order.

See http://www.cdli.ca/courses/phys2204/unit04_org02_ilo15/b_activity.html , which has this figure:

[PLAIN]http://www.cdli.ca/courses/phys2204/unit04_org02_ilo15/les-14-01.gif[/CENTER]

p.s. Welcome to Physics Forums, dima_tr​

 

[dima_tr]

Thanks a lot.

It appears to be really simple :)

 

[sardar]

Hello,

The order of diffraction refers to the number of times a wave is diffracted or bent as it passes through a narrow opening or around an obstacle. This phenomenon is known as diffraction and it occurs when a wave encounters an obstruction or a change in medium, causing it to spread out and bend around the obstacle.

To better understand this concept, let's use the example of light passing through a narrow slit. When a beam of light passes through a narrow slit, it diffracts or spreads out. The resulting pattern of light and dark bands on a screen behind the slit is known as a diffraction pattern.

Now, when we talk about the order of diffraction, we are referring to the number of bright spots or fringes in this diffraction pattern. The first bright spot is known as the first-order maximum, the second bright spot is the second-order maximum, and so on. These bright spots are created due to constructive interference, where the waves from different parts of the slit combine in phase to produce a bright spot.

So, why does the order of diffraction have to be an integer? This is because the number of bright spots or fringes is directly related to the wavelength of the light and the size of the slit. The distance between the fringes is given by the equation d sinθ = mλ, where d is the slit width, θ is the angle of diffraction, m is the order of diffraction, and λ is the wavelength of light. Since m represents the number of fringes, it must be an integer.

I hope this explanation helps you understand the concept of the order of diffraction better. For a visual representation, I suggest checking out this link: . It includes an animation and a detailed explanation of diffraction and the order of diffraction. Best of luck in your understanding!