New Technique Scrambles Light

Cameras and other optical devices are limited by the amount of light that they can collect through their lens openings, or apertures. In order for a light ray to be recorded, it has to pass through the lens and reach the device's "detector" - such as the eye's retina or a digital camera's detector. But many light rays never make it to the detector, either because they are too weak, or because they are deflected.

The new imaging method addresses the shortcomings of small apertures by taking advantage of the unusual properties of substances called nonlinear optical materials. In these materials, light rays mix with each other in complex ways. Rays that don't reach the camera may pass along some of their information to rays that do get recorded by it. Thanks to the mixing of rays, information that would otherwise be lost manages to reach the camera.

The image from a nonlinear lens would therefore be rich in detail. Unfortunately, it would also be distorted - and useless for conventional optics. But if the information could be unscrambled, a computer could reconstruct a high-resolution undistorted image of the entire scene.

To capture the visual information given by the nonlinear material, the Princeton researchers used equipment to take a special type of photograph, called a hologram. They also combined data from a normal camera. As the first step in processing all this information, they created a simplified model of the flow of light through a nonlinear material. Next they developed a mathematical technique that takes the distorted image and works backward to calculate the visual information at every point in space between the image and the object. This method makes it possible to create high-resolution images at any chosen point - at the camera, at the location of the object itself, or somewhere in between.

By capturing information that would normally be lost, the new method could greatly enhance the resolution using normal light - allowing scientists to build microscopes and other devices capable of so-called super-resolution.; Source: Princeton University