Gaussian beam passing through a circular aperture

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SUMMARY

The far-field diffraction pattern of a Gaussian beam passing through a circular aperture is determined by the Fourier transform of the field at the aperture. If the beam size significantly exceeds the aperture, the resulting pattern approximates an Airy function. Conversely, if the beam underfills the aperture, the pattern resembles a Gaussian distribution. Intermediate scenarios yield results that are a convolution of the circular aperture function and the Gaussian beam profile.

PREREQUISITES
  • Understanding of Gaussian beam properties
  • Knowledge of Fourier transforms in optics
  • Familiarity with Airy functions and their applications
  • Concept of convolution in signal processing
NEXT STEPS
  • Study the mathematical derivation of the Fourier transform of a circular aperture
  • Explore the properties and applications of Airy functions in optics
  • Learn about Gaussian beam propagation and its characteristics
  • Investigate convolution techniques in optical systems
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Optical engineers, physicists, and researchers involved in beam propagation analysis and diffraction pattern modeling will benefit from this discussion.

yoni3468
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Hi all,

when I have a Gaussian beam passing through a circular aperture:
What should be the far field (Fraunhoffer's) distribution?

Thanks in advance,
Yoni
 
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The far-field diffraction pattern is the Fourier transform of the field at the aperture. So, it depends on how over- or under-filled the aperture is by the beam. If the beam size is much larger than the aperture, the far-field pattern is close to an Airy function. If the beam severely underfills the aperture, the far-field pattern is nearly a Gaussian. Intermediate cases will present intermediate results- the transform of circ(r/D)*Gaus(ar) = Somb(D*u) # Gaus(u/a), where '#' is the convolution operator, etc.
 
Thank you!

Yoni
 

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