Re: Looking for an Example of Interferometry to Illustrate Increased Resolution

W. Watson wrote:
It might work, but I often deal with people for which some really simple set up or example would be more appropriate. Pretty much I would like something that makes the idea plausible to lay people.

Incidentally, who came up with the idea of using two mirrors separated by some distance to improve the resolution of the image?

Helpful person wrote:
On Jan 29, 4:36 pm, Phil Hobbs <p...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
W. Watson wrote:
I'd be satisfied with with monochromatic sources. The only way I've ever
been able to illustrate the concept, or get across the idea in some way,
the is to take to either cover the aperture of say a Newtonian with a
mask, or cover the surface of the mirror with a mask and show that
individual areas are collectively capable of seeing a star. I may be
fooling myself. In some way it shows that the ability of mirrors
separated can be combined to produce a good quality image. So in a
sense, the concept is "buyable".
That's the spatial filtering idea, done at the pupil--and it sounds like
a good idea. However, a single interference term won't form an image in
laser light either. I don't have a good Fourier optics demo right
handy, but your idea of putting masks on a telescope aperture is a
possibility--maybe you could use strips of coloured tape that you could
take off and put back. That's not a strictly fair demo, of course,
since N source regions will produce N(N-1)/2 spatial frequencies, but
something like that would get the point across.

Cheers,

Phil Hobbs

A possible demo might be Young's douuble slit experiment. This has
two apertures which basically select a single frequency from a delta
function (the source). Change the distance between the slits and you
can see the different frequencies.

It should be possible to extend this to a real object, with the slits
acting as a filter to pass a single frequency. position the slits at
the lens aperture and use various sinusoidal objects. Not necessarily
easy to design, but should work.

www.richardfisher.com


Michelson--his 'Stellar Interferometer'. But that was just to measure the diameter, by looking at the envelope of the fringe pattern, iirc. You really really don't improve an image just by putting fringes in it--you need lots of spatial frequencies.

Cheers,

Phil Hobbs
.

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