21 October 2011
Vol 334, Issue 6054

About The Cover

Cover image expansion

COVER Illustration of a generalized form of Snell's Law that fully accounts for light interaction with subwavelength structured materials, which can produce phase jumps at the interface between media. To illustrate this effect, origami ribbons are folded into tapered cylinders (phase jumps at interfaces), and the lines (light rays) form angles that depend on the degree of taper. Initially diverging rays converge after passing through two interfaces. See page 333. Image: Nanfang Yu/Harvard University; Yi Tan and Jinhua Tan.