A team of researchers at the London Imperial College, under the guidance of Professors Joshua Edel and Alexei Kornyshev, developed a filter on which the distance between nanoparticles can be adjusted. Due to this, its surface can become mirror-like, or transparent, like ordinary glass.
To do this, scientists created the conditions under which gold nanoparticles localize at the interface between two immiscible liquids. By applying a small voltage, they demonstrated the features of a layer of nanoparticles, which, by changing their density, made the surface mirror or transparent.
From the distance between the nanoparticles, it depends on whether the layer passes or reflects waves of light of different lengths. In one mode, all the waves are reflected, and the layer acts as a mirror, and in the other, where the nanoparticles are subjected to dispersion, all the waves pass unhindered through the filter, as through a conventional window.
Unlike previous nanoscopic systems, where the optical properties of the material change irreversibly with the help of chemical action, electrical systems from London are reversible.