1
$\begingroup$

In this manuscript, the author Sidney A.Self mentions about "aperturing effect" at the very last paragraph.

Finally, it should be noted that, throughout this paper, it has been assumed that the lens diameter is sufficient to not significantly aperture the Gaussian beam. If significant aperturing effect occurs, the image position will not be as given above, and the waist will not have a truly Gaussian profile.

What is meant by "aperturing effect"?

$\endgroup$
  • $\begingroup$ Just a guess: could it be the diffraction due to the fact that the lens has a limitated dimension? $\endgroup$ – JackI Dec 23 '16 at 8:44
  • $\begingroup$ Don't forget to accept an answer if one has solved your problem, or ask for clarification in comments if not. $\endgroup$ – uhoh Apr 16 '18 at 12:11
3
$\begingroup$

That statement basically means that the diameter of the lens is larger than the diameter of the Gaussian beam. Now this is a bit wavy, as such beams mathematically extend to infinity. Technically, they are most often limited by windows, apertures, finite size of a detector, ...

It all comes down to how much error you can/want to tolerate. It is somehow trivial that any optical element (lens, mirror, diffraction grating, window) needs to be large enough so that most of your beam goes through.

$\endgroup$
3
$\begingroup$

When light passes through an aperture it is diffracted by the aperture and this will affect the beam profile. For example with a circular aperture the diffraction pattern(in the far field limit) is an Airy disk.

My interpretation of the statement in the paper is that either the apertures are large enough, or the beam length is small enough, that the diffraction has no significant effect on the beam profile.

$\endgroup$
  • $\begingroup$ Actually, in the farfield, a Gaussian field will give a Gaussian profile (which many single mode fiber outputs are) - you don't get the nulls as you do for an abruptly limited circular aperture. Not that this is affects the question or answer. $\endgroup$ – WetSavannaAnimal Dec 23 '16 at 11:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.