Created By : Naaz Fatima

Reviewed By : Phani Ponnapalli

Last Updated : Apr 10, 2023


Diffraction Grating Calculator is a free to use online tool that determines the parameters when a light hits the multi opening structure given the other parameters. All you need to do is enter the respective inputs in the input fields and hit the calculate button to get outputs.

Choose a Calculation
Grating density
Angle of incidence

What is Diffraction Grating?

Diffraction Grating is a wave phenomenon that occurs when a light hits an obstacle with uniformly distributed apertures. Then, the ray gets diffracted and each of them goes into a slightly different direction. We can witness the effects of diffraction only if the spacing between apertures is larger than the wavelength of incident ray.

Diffraction Grating Formula

If the incident light ray is perpendicular to grating you can use the diffraction grating formula to find the direction in which the rays are diffracted. The Diffraction Grating Equation is a * λ = d * sin(Θₐ)

  • Where ╬╗ is the incident ray wavelength
  • d is the grating spacing
  • ╬ÿΓéÉ is the angle between initial and diffracted direction of light for ray a
  • a is an integer = 1, 2, 3......

If the incident ray meets the apertures at an angle Θₒ then you need to include it too in your calculations i.e. a * λ = d * [sin(Θₒ) + sin(Θₐ)]

If the incident ray is at an angle of 30┬░ the equations for first three diffracted images becomes as follows

╬╗ = d * [0.5 + sin(╬ÿΓéü)]

2╬╗ = d * [0.5 + sin(╬ÿΓéé)]

3╬╗ = d * [0.5 + sin(╬ÿΓéâ)]

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FAQs on Diffraction Grating Calculator

1. What is the Principle of Diffraction Grating??

Diffraction Grating is the principle in which ligh ray gets diffracted on hitting an obstacle with uniformly distributed apertures.


2. What is Diffraction Grating Used for?

Diffraction Gratings are used in optical devices such as spectrometers, closely spaced tracks on CDs or DVDs.


3. What is Diffraction Grating Formula?

Diffraction Grating Equation is written by a * λ = d * sin(Θₐ)


4. What are the two types of Diffraction?

The Two Types of Diffraction are Fresnel Diffraction and Fraunhofer Diffraction.