Can you imagine one day using a telescope as thin as a sheet of paper?

[Second Time Around]

Researchers are experimenting now.

https://phys.org/news/2021-06-goodbye-camera-miniaturized-optics-counterpart.html

[Ouroboros]

Is it achromatic? 

[wulfrun]

From the article:

"For example, in every telescope, there is a large gap between the eyepiece and the objective lens to give light room to spread."

Really? Either poorly explained or the writer hasn't a clue what they are talking about.

[old_eyes]

Here is a link to the original paper https://www.nature.com/articles/s41467-021-23358-8#Sec23.

From what I can work out (and please do not trust me on this) they are using a structure of alternating thin films of differint refractive index to mess around with the phase of the wavefront so that the apparent distance travelled in vacuo is dramatically reduced. Reminds me of Fresnel lenses, holographic lenses and other devices from my dim and distant academica past that do optical things in small spaces.

[scotty38]

I remember as a young boy using toilet roll holders as telescopes so "almost" paper thin has already been done 🤣