The ongoing quest for high-resolution space telescopes requires ever-larger optics, but their physical dimensions and weight set practical limits on what can be launched and deployed. Photon sieves offer a lighter-weight alternative. First proposed for x-ray microscopy, a photon sieve is a diffractive element based on a Fresnel zone-plate geometry, which consists of alternating concentric transparent and opaque rings. The opaque rings block the light that would otherwise destructively interfere with light passing through the transparent rings, resulting in only constructive interference at the focus. A photon sieve replaces the transparent rings with many tiny holes, configured so that light diffracting through each of them constructively interferes at a focal point downstream.

The photon sieve shown here is a prototype being developed for next-generation space telescopes by researchers at the US Air Force Academy’s physics department. Since photon sieves are flat, they can be patterned on large, lightweight polymer membranes...

You do not currently have access to this content.