New approach to broadband optical cloaking

Current interest in electromagnetic metamaterials has been motivated to a large extent by the recent work on cloaking and transformation optics. Unfortunately, it appears difficult to develop metamaterials with low losses and broadband performance, which led to experimental realization limited to very small sizes, on the scale of a few wavelengths only.

By using an axisymmetric waveguide between a planar gold film and a gold-coated spherical lens, Vera Smolyaninova (Towson University) I. I. Smolyaninov (BAE Systems), A. V. Kildishev, and V. M. Shalaev (Purdue University) experimentally demonstrated a broadband optical cloaking effect in the visible frequency range for an object, which is 2 orders of magnitude larger than the wavelength of the incident light (Physical Review Letters 102, 213901).

cloak1[1]
Experimental arrangement: A space between gold coated lens and a gold coated glass slide is illuminated with blue (wavelength 488 nm) laser light.  Observation of cloaking is done through the microscope objective (on top).
cloak2[1]
Microscope image showing cloaked area (a dark circle, where light cannot penetrate) at the center of the lens.

Experimental work as done at Towson in Vera Smolyaninova’s lab; supported in part by NSF grant DMR-0348939.

This findings were highlighted in 2Physics, Scientific American, NSF news,  EE times, Eureka Alert of the American Association for the Advancement of Science, V. Smolyaninova’s interview on WYPR “Maryland Morning with Sheilah Kast”, and other general news media around the world.