Details

This Demonstration shows the light intensity pattern due to Fresnel diffraction by a narrow slit. The calculation is based on the Fresnel integrals and , with the intensity distribution on the screen given by , where is the wavelength of the light, is the slit width, and is the distance to the screen. This calculates the optical diffraction of the light that passes a single slit. The theory is based on the traditional Cornu spiral curve.

With the button "pattern" selected, you can vary the wavelength of light, the slit size, and the screen's position to cover any situation. Though this program is very close to the Demonstration "Single-Slit Diffraction Pattern," this version adds the variables "screen position" and "wavelength."

Select "profile" for the linear plot of the diffraction intensity.

Select "clothoid" to see a Cornu spiral and a corresponding red line to read out the diffraction intensity. Set "distance from light axes" to obtain the diffracted light intensity at the position on the screen.