We're one step closer to the stuff of sci-fi and boy wizards. Researchers at the California Institute of Technology have engineered a metamaterial with a refined 3-D structure that gives light a negative refraction index upon entering the material. Put another way, it bends light the opposite way one might expect, irrespective of the angle or polarization of incoming light waves. Put yet another way: We're getting closer to that invisibility cloak we've been looking for.
Metamaterials, of course, are artificial materials engineered to exhibit properties that don't come easily in nature. Such materials could have a range of applications, from superlenses to solar cells to active camouflage. And while this isn't the first light-bending metamaterial we've ever seen, it is the first one that operates on visible light, doing all of its negative-index refracting in the blue part of the spectrum.
Not only that, but this new metamaterial is simpler than previous attempts at negative-index metatamaterials. It requires only a single functional layer, yet is seriously versatile, handling light at any polarization and functioning at a wide range of incident angles. That could potentially enable superlenses that image past the diffraction limit, solar cells that are able to scoop up a lot more sunlight, and even invisibility cloaking.
Previous metamaterials required several layers of resonant elements to create this negative-index response, but the Caltech method requires only a single layer of silver with plasmonic waveguide elements distributed throughout that route the light waves through the material. Involving only a single layer in the process means this new material is easier to manufacture and easier to tune to different wavelengths of light.