THE pill-sized cameras in today’s mobile phones may seem miraculously tiny, given that a decade ago the smallest cameras available for retail sale were the size of a pack of cards. But Ali Hajimiri of the California Institute of Technology is unimpressed. In his opinion even these phone cameras are far too thick (witness the optical bump on the back of most mobile phones), so he and his team plan to replace them with truly minuscule devices that spurn every aspect of current photographic technology. Not only do Dr Hajimiri’s cameras have no moving parts, they also lack lenses and mirrors—in other words, they have no conventional optics. That does away with the focal depth required by today’s cameras, enabling the new devices to be flat. The result, he hopes, will be the future of photography.