Via PhysOrg:
Engineers at UC San Diego have built a powerful yet ultrathin digital camera by folding up the telephoto lens. This technology may yield lightweight, ultrathin, high resolution miniature cameras for unmanned surveillance aircraft, cell phones and infrared night vision applications….
Instead of bending and focusing light as it passes through a series of separate mirrors and lenses, the new folded system bends and focuses light while it is reflected back and forth inside a single 5 millimeter thick optical crystal. The light is focused as if it were moving through a traditional lens system that is at least seven times thicker.
“When all is said and done, our camera will look a lot like a lens cap that can be focused and used as a regular camera,” said Ford.
Their paper is in the latest issue of Applied Optics. (Thanks to Janie for the link!)