Created By : Vaibhavi Kumari

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 17, 2023

Diffraction Grating Calculator is a free online application that calculates the parameters when light strikes a multi-opening structure based on other parameters. To get outputs, simply enter the appropriate inputs in the input fields and press the compute button.

Choose a Calculation
Grating density
Angle of incidence
First order

What is Diffraction?

When a light ray contacts a barrier or a slit, it causes diffraction, which is a wave phenomenon. After passing through the aperture, the light changes direction, causing the wave to expand out.

What is Diffraction Grating?

When light strikes an obstruction with uniformly dispersed apertures, diffraction grating occurs. The rays are then diffracted, with each one travelling in a slightly different direction. Diffraction effects are noticeable only when the distance between apertures is greater than the wavelength of the incident beam.

For more concepts check out to get quick answers by using the free tools available.

Diffraction Grating Formula

If the incident light ray is perpendicular to the grating, the following diffraction grating equation can be used to determine the diffracted ray directions

a * λ = d * sin(Θₐ)

  • Where, λ = wavelength of the incident ray,
  • d = grating spacing,
  • Θₐ = angle between the initial and diffracted direction of light for ray a, and
  • a is an integer - the order of the diffracted image. a = 1, 2, 3..

If the incident ray collides with the apertures at an angle of o, you must account for it in your calculations a * λ = d * [sin(Θₒ) + sin(Θₐ)]

For example, the equations for the first three diffracted pictures for a ray incident at a 30° angle (sin 30° = 0.5) will be as follows: λ = d * [0.5 + sin(Θ₁)] 2λ = d * [0.5 + sin(Θ₂)] 3λ = d * [0.5 + sin(Θ₃)]

How do I Use the Diffraction Grating Calculator?

The following is the procedure how to use the diffraction grating calculator

  • Step 1: In the input field, enter the grating density, angle of incidence, first order and x for the unknown.
  • Step 2: To acquire the result, click the "Calculate the Unknown" button.
  • Step 3: Finally, in the output field, the wavelength will be displayed.

FAQs on Diffraction Grating

1. How can you calculate the spacing between diffraction gratings?

The equation for this is d = 1/N, where N is the number of grooves per unit length(in this case, millimetres). We can see that d is the grating spacing and is the diffraction angle.

2. What is the formula for calculating diffraction?

Given the distance to the screen, the width of the slit, and the wavelength of the light, we can use the equation y = L l / a to calculate where the first diffraction minimum will occur in the single slit diffraction pattern.

3. What is the Diffraction Grating Principle?

The principle of the grating is that when a light beam hits an obstruction having equally distributed openings, it is diffracted.

4. What is the purpose of diffraction grating?

Diffraction Gratings are employed in optical devices such as spectrometers and CD or DVD tracks that are closely spaced.