Even as our phones get thinner, there's one spot that keeps sticking out: the camera lens. Taking good pictures and being able to focus at multiple distances requires a layer of glass that's a certain size, but there's really no getting around it -- or is there? Researchers at Caltech have devised (PDF) an "optical phased array" chip that uses math as a substitute for a lens. By adding a time delay -- down to a quadrillionth of a second -- to the light received at different locations on the chip, it can change focus without a lens.
Source: Caltech, An 8X8 Heterodyne Lens-less OPA Camera (PDF)