Diffraction Patterns

Application ID: 117

This example resembles the well-known 2-slit interference experiment often demonstrated in schools with water waves or sound. This model mimics the plane-wave excitation with two thin waveguides leading to slits in a screen, and it computes the diffraction pattern on the screen’s other side.

This diffraction pattern is clearly visible. The main effect of quantization is that the numerical wavelength differs from lambda and thus results in a systematic shift in the angles. You could correct for this effect by adjusting the value of k, in the Helmholtz equation, to the element size. Such practices are important when you wish to faithfully model interference effects of monochromatic waves.

This model example illustrates applications of this type that would nominally be built using the following products:

COMSOL Multiphysics®