Description

Multiple Slit Diffraction

The EJSS 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:

D sin Ө = m λ , where m = 1,2,3,......

where D is the single slit width.

For double slit interference, constructive interference (bright spots) are found at:

d sin Ө = m λ , where m = 1,2,3,......

and destructive interference dark spots are located at:

d sin Ө = (m+0.5) λ , where m = 1,2,3,......

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 JavaScript Simulations (EJSS) modeling tool. It was adapted to EJSS 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 EJSS installed by right-clicking within the diffraction frame and selecting "Open Ejss 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/"

This remixed model is by Lookang based on the earlier EJSS models by Fu-Kwun Hwang, Robert Mohr and Wolfgang Christian and Andrew Duffy.