Only one wavelength bounces back; others pass through unimpeded
V.S. Asadchy et al/Physical Review Letters 2015
Mirrors need not be equal-opportunity reflectors.
A newly fabricated mirror reflects only a single wavelength of light; all other wavelengths pass through undisturbed. Introduced in the March 6 Physical Review Letters, the mirror is the latest device constructed from metamaterials — synthetic substances composed of structural elements that manipulate desired wavelengths of light. Similar “metamirrors” could eventually replace bulky, expensive radio dishes used for communication and astronomy.
Conventional mirrors contain a silvery layer that reflects a broad range of light, including the entire visible spectrum. The metamirror designed by physicist Viktar Asadchy and colleagues at Aalto University in Finland looks very different: It consists of millimeter-sized loops of copper wire embedded in plastic.
Researchers illuminated the mirror with microwaves. The 60-millimeter