Light is scattered and absorbed as it travels through turbid media such as fog, cloud, and dirty water, making it difficult to image objects that may be hidden within. Some light, however, passes through ballistically—that is, without loss—and capturing that ballistic light offers the potential for imaging otherwise hard-to-see objects. Zevallos et al. show that combining ultrashort pulses (130 fs) of light with a pulsed detection system (80-ps window) can improve the contrast between the buried object and the noisy background that arises from the diffuse light scattered from the surrounding turbid material; the brief window lets in most of the ballistic light and only a little of the noise, thereby providing a clearer snapshot. The ability to improve the imaging of objects normally hidden from view has a whole host of applications, from the medical imaging of biological tissue to remote sensing and underwater surveillance. — ISO
Appl. Phys. Lett. 86, 011115 (2005).