Consider a support made from a wide (1m), short (30cm) (approximate sizes just for reference), rigid, empty, open ended cylinder. Cover the ends with a perfectly flexible transparent sheet. Suck the air out of the contraption. It should look somewhat like a concave lens. The sketch below provides a section view of the "lens".
1 - Would this "lens" concentrate light ?
- I am assuming it would act like a lens because of the difference in density between the inside medium and the outside medium. I am suspecting it would concentrate light because the medium inside is less dense than the outside so it should have the opposite effect of a solid glass concave lens.
2 - What shape will the membranes take under pressure? Will it take the shape that's necessary for a lens?
Temporary Edit to address the "off topic" issue:
I did a search in physics SE for "What shape" and found lots of questions asking what shape would x material take under x circumstances. Why is mine different? Just because this physics concept would be used in some engineering project later on?