Abstract

As an image-bearing wave traverses a scattering medium, the phase of the wave becomes severely distorted. Although most of the light is multiply scattered, a small fraction of the light will be scattered much less than average, and so may still contain information about the original incident wave front. Because this barely-scattered light is extremely weak, it is usually overwhelmed by the multiply-scattered light, so that no image can be observed by eye. Note, however, that the wave that is barely scattered (or not scattered at all) travels a shorter path to the observer's eyes than does the multiply-scattered part of the wave. If the original image-bearing beam is an ultrashort pulse, then in principle, by replacing the eye with a fast, time-resolving detector, one could discriminate between the unscattered, image-containing part of the transmitted light and the multiply-scattered background light. One might use this technique to observe objects embedded in a strongly scattering medium, such as living tissue, if only a fast enough "shutter" could be developed to cut off the strong background of scattered light.

© 1991 Optical Society of America