RP Photonics

Encyclopedia … combined with a great Buyer's Guide!

VLib
Virtual
Library

Beam Collimators

Definition: devices for collimating optical beams

German: Kollimatoren, Strahlkollimatoren

Categories: general optics, lasers

How to cite the article; suggest additional literature

The purpose of a beam collimator is essentially to transform a strongly diverging light beam into a collimated beam, i.e., a beam where light propagates essentially only in one direction, and the beam divergence is weak. The output beam may have its focus close to the output aperture, or a mild focus somewhat away from it (see Fig. 1).

Essentially, a beam collimator contain some kind of focusing lens, or sometimes a curved mirror, and usually some opto-mechanics for stable mounting and possibly adjustment.

Typically, beam collimators are applied in conjunction with the following types of light sources:

collimated beam
Figure 1: Beam radius versus position in a set up where a tightly focused beam is collimated with a lens, generating a mild focus somewhat behind it.

In many cases, the collimation is done in both directions perpendicular to the beam, but there are also beam collimators working in one direction only – for example, fast axis collimators attached to certain laser diodes.

Typical Requirements

The requirements on a beam collimator can be very different, depending on the light source with which it is used:

fiber collimation
Figure 2: Fiber collimator with an aspheric doublet lens, not including the mechanical mount.
  • Some light sources exhibit a strong beam divergence, and it is then often necessary to use aspheric optics to avoid significant beam quality deterioration due to spherical aberrations.
  • In some cases, the beam is strongly asymmetric, with much stronger divergence in one direction than the other. A simple beam collimator may then produce an elliptical beam, but one may apply additional elements such as an anamorphic prism pair for obtaining a circular beam profile.
  • While some collimators can be used with a fixed alignment, others need to be adjustable, at least concerning the focus, which can be modified through the distance between light source and collimation lens.
  • The beam pointing stability of the generated beam depends on how mechanically stable the setup is. Note that tiny thermal drifts, for example, may cause significant changes of beam direction particularly in cases where the focal length of the collimating lens is small.
  • Some devices need to work with very high optical powers, so that one needs to minimize propagation losses and avoid thermal effects.

Suppliers

The RP Photonics Buyer's Guide contains 29 suppliers for beam collimators. Among them:

See also: collimated beams, fiber collimators, laser diode collimators, parabolic mirrors
and other articles in the categories general optics, lasers

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
Comments:

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:

arrow