Light-field camera snaps dusty plasma

Dusty plasmas consist of charged microparticles embedded in a lightly ionized gas (see Physics Today, July 2004, page 32). In space, such plasmas pervade planetary rings. In the lab, where higher microparticle densities can be achieved, the plasmas form crystals, melt, carry waves, and exhibit other collective behavior. Observing the microparticles, which dominate the dynamics, is tricky. Although individual particles are large enough to resolve using optical techniques, monitoring all of them requires a combination of magnification and depth of field that standard cameras lack. Péter Hartmann of the Institute for Solid-State Physics and Optics in Budapest, Hungary, and his colleagues are tackling the problem by using a nonstandard camera, the Lytro. Thanks to an array of microlenses that sits between the camera’s main lens and detector, the Lytro and its built-in software can determine not only the direction of incoming light (corresponding to the x and y...