# Single Slit Diffraction

 Single slit Double slit Three slits Five slits
 Diffraction and interference Interference only

Under the Fraunhofer conditions, a single slit will exhibit a light curve following the single slit diffraction intensity expression. The narrower the slit, the broader the peaks of light. The shape or "envelope" of this light curve will serve to set limiting intensities for multiple slit arrangements, assuming that all the slits are identical.

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Index

Diffraction concepts

Fraunhofer diffraction

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# Double Slit Diffraction

 Single slit Double slit Three slits Five slits
 Diffraction and interference Interference only

Under the Fraunhofer conditions, the light curve (intensity vs position) is obtained by multiplying the multiple slit interference expression times the single slit diffraction expression. The multiple slit arrangement is presumed to be constructed from a number of identical slits, each of which provides light distributed according to the single slit diffraction expression. The multiple slit interference typically involves smaller spatial dimensions, and therefore produces light and dark bands superimposed upon the single slit diffraction pattern.

 Show example with HeNe laser
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Index

Diffraction concepts

Fraunhofer diffraction

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# Three Slit Diffraction

 Single slit Double slit Three slits Five slits
 Diffraction and interference Interference only

Under the Fraunhofer conditions, the light curve (intensity vs position) is obtained by multiplying the multiple slit interference expression times the single slit diffraction expression. The multiple slit arrangement is presumed to be constructed from a number of identical slits, each of which provides light distributed according to the single slit diffraction expression. The multiple slit interference typically involves smaller spatial dimensions, and therefore produces light and dark bands superimposed upon the single slit diffraction pattern.

 Show intensity comparison
Index

Diffraction concepts

Fraunhofer diffraction

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# Five Slit Diffraction

 Single slit Double slit Three slits Five slits
 Diffraction and interference Interference only

Under the Fraunhofer conditions, the light curve (intensity vs position) is obtained by multiplying the multiple slit interference expression times the single slit diffraction expression. The multiple slit arrangement is presumed to be constructed from a number of identical slits, each of which provides light distributed according to the single slit diffraction expression. The multiple slit interference typically involves smaller spatial dimensions, and therefore produces light and dark bands superimposed upon the single slit diffraction pattern.

The progression to a larger number of slits shows a pattern of narrowing the high intensity peaks and a relative increase in their peak intensity. This progresses toward the diffraction grating, with a large number of extremely narrow slits. This gives very narrow and very high intensity peaks that are separated widely. Since the positions of the peaks depends upon the wavelength of the light, this gives high resolution in the separation of wavelengths. This makes the diffraction grating like a "super prism".

 Show intensity comparison
Index

Diffraction concepts

Fraunhofer diffraction

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