Proposed Telescope Focuses Light Without Mirror Or Lens

A team of scientists from Observatoire Midi Pyrénées in Toulouse, France have been working with an unusual technique for focusing light. It takes advantage of diffraction - the bending of waves when they encounter an obstacle in their path - to focus light as it passes through a foil sheet with precise holes in it. The scientists suggest that an orbital 30-meter imager could resolve planets the size of Earth within 30 light-years. In addition, the foil is much lighter than traditional materials, and thus easier to transport. "A Fresnel imager with a sheet of a given size has vision just as sharp as a traditional telescope with a mirror of the same size, though it collects just 10% or so of the light. It can also observe in the ultraviolet and infrared, in addition to visible light. The imager can take very detailed images with high contrast, which is great for 'being able to see a very faint object in the close vicinity of a bright one.'"

Comments

Looks like a sail...

[sapphire wyvern]

Hmm, a large flat surface with holes in it.

It looks like launching one of these babies would require solutions to the same technical problems as solar sails, ie stowing & unfolding once in orbit.

Would it be possible to have the sheet do double duty, acting as both a Fresnel "lens" and a means of propulsion for the spacecraft? That might be a neat way of getting the instruments to a good location.

Not for amateurs...

[syousef]

I was thinking hey neat till I read this in the article.

For one thing, the light comes to a focus far away from the foil sheet - with distances measured in kilometres, which means the camera and other instruments have to be mounted on a separate spacecraft. The instrument spacecraft would have to stay precisely aligned with the foil sheet, to within a millimetre or so.

Certainly not impossible, and still exciting, but this isn't going to be a mainstream or amateur tool any time soon.

Looks like there also may be a related patent to get past...

http://www.patentstorm.us/patents/6375326-claims.html