Principle
Multiple slits which all have the same width and the same
distance among each other, as well as transmission grids with
different grid constants, are submitted to laser light. The
corresponding diffraction patterns are measured according to their
position and intensity, by means of a photo diode which can be
shifted.
Benefits
- understand what makes an optical grid work, by approaching it
via "multiple slits"
- the coherent light of a laser gives the possibility of easy
observation
- clear correlation of measurement results to the underlying
theory
Tasks
- The position of the first intensity minimum due to a single
slit is determined, and the value is used to calculate the width of
the slit.
- The intensity distribution of the diffraction patterns of a
threefold, fourfold and even a fivefold slit, where the slits all
have the same widths and the same distance among each other, is to
be determined. The intensity relations of the central peaks are to
be assessed.
- For transmission grids with different lattice constants, the
position of the peaks of several orders of diffraction is to be
determined, and the found value used to calculate the wavelength of
the laser light.
What you can learn about
- Huygens principle
- Interference
- Fraunhofer und Fresnel diffraction
- Coherence