In a study published July 10 on Nature Photonics’s website, Serdar Kocaman, an electrical engineering Ph.D. candidate, and Chee Wei Wong, associate professor of mechanical engineering, demonstrated how an optical nanostructure can be built that controls the way light bounces off it. When light travels, it bends—in technical terms, it disperses and incurs “phase,” an oscillating curve that leaves a trail of information behind it. Those oscillations show an object’s properties, such as shape and size, which can identify it. However, light hits Kocaman’s and Wong’s specially engineered material without leaving a trace. Every natural known material has a positive refractive index: when light hits it, the light bends or refracts. The researchers engineered a structure in which they etched tiny holes, creating a material known as a “photonic crystal” which behaves as though it has zero index – light can travel with an ultrafast

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