Appl. Phys. Lett. 104, 171102 (2014)

Perfect reflectors are desirable for protecting surfaces against high-power irradiation, creating low-loss mirrors in laser cavities and improving the signal-to-noise ratios in bioimaging and nanosensing applications. Now, researchers from Vanderbilt University and SRI International in the USA have designed and fabricated broadband near-perfect reflectors that operate in the telecommunications wavelength band by utilizing all-dielectric metamaterials that exploit Mie resonances. They used a single-negative metamaterial consisting of silicon cylinders (height, 500 nm; diameter, 400 nm) positioned in a 660-nm-period array on a silicon-on-insulator wafer. This reflector exhibited an average reflectance of more than 98.0% over the infrared wavelength range 1,355–1,555 nm. The researchers also investigated the relationship between the degree of disorder of the metamaterial and its reflectance; they found that the near-unity reflectance is maintained provided the cylindrical resonators are not positioned so close to each other that they mutually interact. This raises the possibility of fabricating large-area reflectors using inexpensive, high-throughput fabrication techniques, such as nanosphere lithography and self-assembly.