Revisiting Diffraction with an Apodized "Iris"

Started Aug 15, 2017 | Discussions thread
(unknown member) Senior Member • Posts: 2,498
Re: Revisiting Diffraction with an Apodized "Iris"

Joofa wrote:

AiryDiscus wrote:

Joofa wrote:

OpticsEngineer wrote:

Looks pretty good, matching what Zemax shows using Gaussian apodization with an apodization factor of 2. A(r) = exp(-2*r^2)

I didn't participate in the previous thread on this. But in case it was of interest to someone, we get pretty much complete suppression of the Airy rings with an apodization factor of 1 (A(r)=exp(-r^2) ) without reducing the high frequency response nearly so much.

Apodization is just what is known as 'windowing ' in signal processing. An area of much practical usage in EE. And the Fourier Transform of a Gaussian is well-known. So there should be no surprises here.

Is the Fourier transform of a complex function whose magnitude is a gaussian multiplied by a circ() and whose phase is complicated well know?

In this case it is just the Fourier transform of a (possibly truncated) Gaussian. No need to make it sound more complicated than it is.

Except that it is a circular aperture, so everything comes out in terms of Bessel functions, not sinusoids...


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