The Government of Canada’s terminology and linguistic data bank.


Record 1 2015-02-17


Subject field(s)
  • Optics

The resolution of an optical imaging system – a microscope, telescope, or camera – can be limited by factors such as imperfections in the lenses or misalignment. However, there is a fundamental maximum to the resolution of any optical system which is due to diffraction. An optical system with the ability to produce images with angular resolution as good as the instrument's theoretical limit is said to be diffraction limited.


  • Optique

En optique ondulatoire, un système idéal imageant parfaitement un point objet n'est limité que par la diffraction, c'est-à-dire que seule la diffraction intervient et que les aberrations ne déforment pas le front d'onde.


Limite de diffraction – Les instruments optiques contiennent le plus souvent une chambre noire. La lumière passant par l'ouverture de la chambre noire subit une diffraction. Or la diffraction limite le pouvoir de résolution des instruments optiques : un objet ponctuel donne une image «floue», appelée tache de diffraction. Si deux détails d'un objet sont trop proches, les taches de diffraction se chevauchent et il devient impossible d'obtenir des images séparées de ces détails.


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Record 2 1991-01-03


Subject field(s)
  • Computer Graphics
  • Lasers and Masers
  • Radar, Radio Guidance and Goniometry

The limit set by the degree of coherence which is attained. The smallest focused spot that can be obtained is when the laser output is derived entirely from the uniphase mode of oscillation.


  • Infographie
  • Masers et lasers
  • Radar, radioguidage et radiogoniométrie


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