Physicists at the Max Planck Institute for Quantum Optics (MPQ) have developed the lightest optical mirror. The new metamaterial is made of a single structured layer consisting of only a few hundred identical atoms. Atoms are located in a two-dimensional array of the optical lattice. The research results are the first experimental observations in a new field of subwavelength quantum optics with ordered atoms. This mirror is one of a kind.
Typically, mirrors use highly polished metal surfaces or optical glasses with a special coating to improve performance with less weight. But physicists from MPQ have demonstrated for the first time that even one structured layer of several hundred atoms can form an optical mirror. Its thickness is only a few tens of nanometers, which is a thousand times thinner than the width of a human hair.
Engineers noted that the two main characteristics of the mirror are regular pattern and wavelength. They suppress diffuse light scattering, combining reflection into a unidirectional and stable beam of light. Moreover, due to the relatively close and discrete distance between the atoms, the incoming photon can bounce back and forth between atoms many times before being reflected. Both effects make the mirror more effective.
The diameter of the mirror is about seven microns. However, the device on which the mirror was constructed occupies the entire territory of the laboratory of scientists – it has more than a thousand individual optical components and weighs about two tons. Therefore, the new material is unlikely to be used for the mass production of mirrors.