“Squeezed light” used to monitor molecules inside living cells

MIT Technology Review : A lot of internal cellular activity occurs at subnanometer scales. Such activity is hard to view with conventional imaging techniques because of diffraction, or the way that light shone on an object is deflected as it strikes tiny particles in the object. The amount of diffraction depends on a phenomenon called quantum noiseâmdash;uncertainties concerning the light photons’ positions. A new technique developed by Michael Taylor of the University of Queensland, Australia, and his colleagues uses “squeezed light"âmdash;carefully manipulated photons that reduce the amount of quantum noise. The researchers were able to attain a resolution of 10 nm, a 14% improvement over conventional imaging. The technique has allowed them to monitor the motions and interactions of nanoparticles inside a living cell. By monitoring multiple areas throughout the cell, they were able to create a map of nanoparticle diffusion patterns. And because of the lower diffraction rate, they were also able to image the cell to the same resolution as conventional techniques but at much lower light intensity, and therefore less risk of damage to the cell.