Recent content by kmartin

The light has to be polarised as the angular dependent refractive index only works when the polarisation is in the same plane as the crystal's optic axis and the propagation direction. However it would be possible to split the light into its two polarisations and process them separately to...

Its nice to know I'm not going completely mad. Thanks :smile:

The effective refractive index is given by n(\vartheta) where \frac{1}{n(\vartheta)^2} = (\frac{cos(\vartheta)}{n_o})^2+(\frac{sin( \vartheta)}{n_e})^2 http://www.radiantzemax.com/kb-en/KnowledgebaseArticle50260.aspx For calcite n_o=1.658 n_e=1.486...

The angular dependent path difference comes from the angular dependence of the birefringent crystal. Small changes in propagation direction cause small changes in the effective refractive index, which cause small changes in the optical path length.

Here's a (hopefully) better explanation. Consider two identical telescopes a few metres apart, both pointing at the same far away light source. The images formed by the two telescopes are indistinguishable because the source is far way. However if the images are combined they can create a...

I think the more important question is: Can you use a birefringent crystal to adjust the phase in order to mimic the effect of translating a telescope laterally?

That design has two big mirrors. The design in the opening post just has one, so it is very different.

If it worked then it could potentially allow the construction of a small relatively cheap space telescope that has a resolving power much greater than any current telescope*. Also it could make conventional astronomical interferometry obsolete, as only one big telescope is required. So its...

Thanks for the replies, but I don't think they really answer my main question. To put it another way, if I could measure the phase of the light at every point of the focused image of a telescope, as well as the intensity, wouldn't that give me more information about the light source than a...

Is it possible for a telescope to resolve images beyond the diffraction limit? In other words, is the information in the light entering a telescope insufficient to resolve beyond the diffraction limit, or is information lost when the light is focused onto a screen? Attached to this post is a...