- Given a circular aperture 0.2 mm in diameter illuminated by a normally incident plane wave field of wavelength l = 632.8 nm. If we wish to observe a region of 50 mm in diameter in the fresnel region, how close can we be to the aperture? How far away must we be to observe fraunhofer diffraction?
- A single slit in an opaque scren 0.10 mm wide is illuminated (in air) by plane waves from a krypton ion laser (l = 461.9 nm). If the observing screen is 1 m away, calculate the Fresnel number and determine whether the resulting pattern is far-field. Then calculate the angular width of the central maximum.
- A narrow single slit (in air) in an opague screen is illuminated in the infrared from
a He-Ne laser at 1152.2 nm, and it is found that the center of the 10
^{th}dark band in the fraunhofer pattern lies at an angle of 6.2 degrees off the central axis. Determine the width of the slit. - A collimated beam of microwaves impinges on a metal screen that contains a long horizontal slit that is 20 cm wide. A detector moving parallel to the screen in the far-field region locates the first minimum of irradiance at an angle of 36.87 degrees above the central axis. Determine the wavelength of the radiation.
- Use Matlab and the function
`fresnel`to plot the Cornu spiral. - Use the Matlab integration function
`quad`to calculate values for the Fresnel integral from 0.0 to 5.0 in steps of 0.5. Compare the results obtained by the function`fresnel`. - Use Matlab to plot the on-axis irradiance of a normalized slit vs. Fresnel number.
- Use Matlab to plot the irradiance of a normalized slit for
*N*= 5/2 and_{f}*N*= 2/5._{f}

Maintained by John Loomis,
last updated *8 June 2012 *