About

Multiple Slit Diffraction

The EJS Multiple Slit Diffraction model allows the user to simulate Fraunhofer diffraction through single or multiple slits. The user can modify the number of slits, the slit width, the slit separation and the wavelength of the incident light. The scale of the diffraction pattern can also be changed and a plot of the light intensity can be toggled on and off with a checkbox.

 

The minima of single slit diffraction are determined by:

where D is the single slit width. For double slit interference, constructive interference (bright spots) are found at:

and destructive interference dark spots are located at:

where d is the distance between slits.

Multiple slits will sharpen (narrow) the regions of constructive interference.  The overall pattern from multiple slits will be the two-slit pattern multiplied by the single slit diffraction envelope.

References:

• Douglas Giancoli, Physics: Principles with Applications sixth edition, pages 664-675.
• Eugene Hecht, Optics fourth edition, pages 460-464.

Credits:

The Multiple Slit Diffraction model was created by Fu-Kwun Hwang using the Easy Java Simulations (EJS) modeling tool. It was adapted to EJS version 4.1 by Robert Mohr and Wolfgang Christian at Davidson College. You can examine and modify the model for this simulation if you have EJS installed by right-clicking within the diffraction frame and selecting "Open Ejs Model" from the pop-up menu. Information about EJS is available at: <http://www.um.es/fem/Ejs/> and in the OSP ComPADRE collection <http://www.compadre.org/OSP/>.

 

Translations

Code	Language		Translator	Run

Credits

Fu-Kwun Hwang; Robert Mohr; Wolfgang Christian; Félix J. García Clemente; Francisco Esquembre; converted to JavaScript ejss by lookang

 

Sample Learning Goals

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For Teachers

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Research

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Video

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 Version:

1. https://weelookang.blogspot.com/2021/08/multiple-slit-diffraction-javascript.html
2. https://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2804.msg10149#msg10149
3. https://www.compadre.org/osp/items/detail.cfm?ID=8331

Other Resources

https://www.compadre.org/osp/items/detail.cfm?ID=16739 by Wolfgang Christian using Plotly library

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