RP Photonics

Encyclopedia … combined with a great Buyer's Guide!


Gaussian Optics

Definition: a framework for describing optical phenomena, which is based on geometrical optics and the paraxial approximation

German: Gauß-Optik

Category: general optics

How to cite the article; suggest additional literature

Gaussian optics is a framework for describing optical phenomena, which is based on geometrical optics (ray optics) and makes extensive use of the paraxial approximation. It has been developed by Johann Carl Friedrich Gauss (1777 – 1855) and is still widely used for many purposes.

The essential assumptions on which Gaussian optics is based are the following:

It is no problem that substantial angles can be involved e.g. in refraction at prisms; at those optical components, the optical axis can also be assumed to be bent. Only angles relative to the optical axis need to be small.

Under the mentioned assumptions, a substantially simplified mathematical description of optical phenomena is possible:

One can also apply the related rules in geometrical drawings.

The described framework can be applied to a wide range of optical systems – for example, to telescopes, photo cameras and microscopes. One can calculate parameters like focal lengths, the transverse, linear and longitudinal magnification, identify conjugate planes, focal planes, image planes etc. However, important phenomena like optical aberrations cannot be treated, because those involve geometrical nonlinearities which are neglected in Gaussian optics. Their treatment requires substantially more sophisticated mathematical methods. One can consider Gaussian optics to provide a simplified description, which is relatively easily calculated, and aberrations (as calculated with more sophisticated methods) are deviations from that.

Although Gaussian optics belongs to the methods of geometrical optics, various parameters have a direct correspondence to quantities in wave optics. Therefore, it is possible, for example, to describe the propagation of Gaussian beams (including wave effects like diffraction) based on parameters calculated with Gaussian optics.

Note that the well known Gaussian beams are not appearing in the realm of Gaussian optics; they belong to wave optics.

See also: geometrical optics, paraxial approximation, image planes, cardinal points, principal points and principal planes, ABCD matrix
and other articles in the category general optics

How do you rate this article?

Click here to send us your feedback!

Your general impression: don't know poor satisfactory good excellent
Technical quality: don't know poor satisfactory good excellent
Usefulness: don't know poor satisfactory good excellent
Readability: don't know poor satisfactory good excellent

Found any errors? Suggestions for improvements? Do you know a better web page on this topic?

Spam protection: (enter the value of 5 + 8 in this field!)

If you want a response, you may leave your e-mail address in the comments field, or directly send an e-mail.

If you enter any personal data, this implies that you agree with storing it; we will use it only for the purpose of improving our website and possibly giving you a response; see also our declaration of data privacy.

If you like our website, you may also want to get our newsletters!

If you like this article, share it with your friends and colleagues, e.g. via social media: