A Metamaterial for Superscattering Light

Light scattering is a common optical phenomenon, much like reflection, refraction, and absorption. Small molecules in the atmosphere scatter sunlight more efficiently at the shorter wavelengths of the solar spectrum, giving the sky its blue color on a clear day. And larger vapor droplets scatter light over the entire visible spectrum, lending clouds their white appearance. In general, the intensity and direction of the scattered light depend on its wavelength and on the characteristics of the scatterer—such as size, geometry, and refractive index. Researchers have tuned these characteristics to engineer structures that scatter light in specific—and often surprising—ways. Schemes for diminished scattering, or “cloaking,” have been proposed or realized [1, 2], as have schemes that selectively enhance scattering in a desired direction [3–5]. Now, a team led by Hongsheng Chen at Zhejiang University, China, and Baile Zhang at Nanyang Technological University, Singapore, has designed a subwavelength-sized structure whose ability to scatter light is greatly enhanced, providing the first experimental demonstration of the so-called superscattering effect [6]. This phenomenon could be harnessed for a variety of applications, from boosting the efficiency of antennas and energy-harvesting devices to improving the resolution of imaging schemes.